Tongues (whether speaking in the heavenly type (i.e. the language of angels/language spoken to God through the power of the Holy Spirit) or speaking in the form of foreign earthly languages (ex. French, Spanish, Hindi, Malayalam, English, etc.) are a gift not given to all believers. I've never been able to speak to God in a heavenly language. I have experienced talking to God through the groaning of the Holy Spirit (which is different from tongues)- refer to Romans 8:26-27. If a believer wants the gift of tongues (whichever form of it), they can ask God for it. If the Holy Spirit gives it to them according to His will, then that's fine. However, if the Holy Spirit doesn't give the gift to someone, that doesn't mean they are not a believer or haven't fulfilled the requirement of undergoing baptism of the Holy Ghost and must keep waiting for it (as Pentecostals teach). Thus, charismatics should not be discriminating and harassing such people. When they do that, they invite God's own judgment against themselves. When Christians start persecuting among themselves, it shouldn't be a surprise when God allows their enemies (ex. Hindus, Muslims, etc.) to attack and mock them (refer to Hindus attacking Pentecostal churches and RSS person posing as a Pentecostal pastor). These sociopaths among Christians won't get away with their carnal behavior for long. God knows how to deal with them and He has them surrounded by even bigger enemies like I just stated above. That's why they should live in fear of God by getting rid of their carnal minded doctrines, false teachings, discrimination, and licentiousness. In other words, it's time to repent. Learn from the example of Israel in the Old Testament. God allowed them to rebel and prosper for a while, but then allowed their enemies to overpower them and send them into exile. In the modern era, judgment will start with the Church, and I will not be surprised when God judges carnal minded Christians through their enemies surrounding them.
The whole purpose of spiritual gifts is to edify others (teach, encourage, help, and show godly love to them), not glorify one's self to satisfy one's own narcissistic ego (to show off one's spirituality to impress/dominate others) and also make money off of such fake spirituality (which I believe many pastors have found a business/income through such deception). I believe that there can be fake/demonic forms of glossolalia (tongues) which can be used to deceive/impress others with a fake form of spirituality. That's why I believe the Bible states that interpreters must be available to interpret tongues when used in a public gathering- in order to distinguish between the work of the Holy Spirit and the work of demonic spirits (refer to Choreographed healing services of charismatics).
I say again, speaking in tongues is not a mandatory requirement for believers to demonstrate that they have received baptism of the Holy Ghost (which many Pentecostals live in denial of this truth). Living in denial is actually one of the many ego defense mechanisms. Even the Plymouth Brethren/Kerala Brethren are guilty of using various ego defense mechanisms to form false doctrines (just like the Pentecostals do). For example, in the case of the Brethren, they project their sins (past, present, future sins) onto Christ through their doctrines of penal substitutionary atonement and imputed righteousness. This allows them to live in denial that they actually need to get rid of their sinful behavior. They rationalize and intellectualize (which are other ego defense mechanisms) licentiousness through false doctrines. Thus, they end up promoting licentiousness (which is evident in many of their churches as many of them have turned into dangerous sociopaths- people with dead consciences who have no problem in sinning). Out of Satan's hatred for Christianity, he influences carnal minded "Christians" (those who love and justify licentiousness through their doctrines) to destroy their churches as well as themselves. That's why he's the ultimate sociopath (he causes problems between people as well as get them to destroy themselves). Satan markets his carnal minded/false form of Christianity to people as it appeals to their sinful nature. Just like how people market unhealthy food, sodas, etc. which destroy the body and which also appeal to man's sinful nature, in a similar way, Satan markets carnal minded Christianity to destroy both body and soul (i.e. make man subject to God's eternal punishment by not getting rid of sin from their lives, but instead deceive them to justify it through deceptive doctrines). Satan has turned them into narcissistic sociopaths (mentally abnormal people- aka antisocial personality disorder) through their carnal minded doctrines. The Brethren also are guilty of teaching erroneous teachings regarding tongues (as they deny it's existence in the modern church, altogether- they are cessationalists). Thus, both Pentecostals (charismatics) and the Brethren have Satan working through the false teachers among them. Both have teachers among them who twist and distort Scripture to promote false doctrines. Thus, Satan has turned many churches among both of their groups into cults. Just look at the preacher in this video who kept saying that anyone who doesn't speak in tongues is not a Pentecostal. Lol. That's a classic characteristic of a cult leader. The Bible doesn't teach for us (believers) to divide and classify ourselves according to man made classifications (ex. Brethren, Baptist, Pentecostal, Mar Thoma, Catholic, etc.) and requirements. Only cults do that. The Bible only gives believers one name- Christians (followers of Christ). We should not be followers of the various isms created by men (ex. Brethrenism, Pentecostalism, etc.) nor be known by their names. We are called by His own name (i.e. Christ- Christian or in other words a follower of Christ).
1 Peter 4:16 (NLT):
But it is no shame to suffer for being a Christian. Praise God for the privilege of being called by his name!
It's a nightmare being in any Malayalee church today (Brethren, Mar Thoma, Pentecostal, etc.). All denominations have been infiltrated by sociopaths (Satan's own children) who teach false doctrines as well as love to start fights directly with people (as evidenced through many of the Youtube clips available of Malayalee Bible teachers/pastors attacking each other through social media) and also indirectly start fights between people who they don't like (i.e. get their enemies to fight each other while they stand and watch). It's all inspired and influenced by Satan. They are his henchmen. All these denominations need to dissolve and genuine believers need to separate themselves from these cults and start their own house churches (not influenced by the seminaries and Bible colleges which are controlled by Satan to influence them into adopting false and man made doctrines which have man made agendas behind them). In many of these carnal minded churches, elitism is a common factor I've been observing through their doctrines and practices (i.e. people wanting to dominate others and then using false doctrines to justify such behavior).
There is absolutely no point of trying to reason with sociopathic false teachers (whether Pentecostal, Brethren or other denomination) who live in denial of the truth and instead try to force their false views onto you. You're dealing with mentally ill people (sociopaths) who will only take you around in circles (i.e. gaslight you) with their flawed logic/reasoning.
I remember reading a comment from a Brethren person for the above Youtube clip. This person was saying how such Pentecostal teachers can't fool everyone and regarding the criticism of Pentecostals against the Brethren, they further stated of how Brethren churches with intelligence and God's love would rise up. I replied to that person in the following way: "How is that possible when they themselves are known to be sociopaths? Their entire theology is based on sociopathic ideologies like Calvinism/Free Grace theology (which promote licentiousness). Once, I heard a Brethren preacher say that the Brethren churches have a problem in them regarding their members pecking at each other like birds do. This is God's love? The Malayalee Brethren churches are also known for being hypocrites (just like other Malayalees/Indians who aren't Brethren/Christians). They love to find sins in others and then go gossip about that and bully/mistreat them (all the while preaching that everyone among them has been atoned for by Jesus' blood, they have imputed righteousness, unconditional eternal security, and the dispensation of grace in order to sin without any consequences and not be judged by God nor anyone else). Many of them are also experts at destroying people's faith in God by instilling psychological blocks in their minds by making them doubt success in their education and career. Again, how is this displaying God's love? They are a Satanic cult who have sociopathic elitists among them who love to dominate others. They act just like their real father Satan, as they also engage in trying to steal, kill, and destroy people. These sociopathic elitists can do whatever sins they want and subject everyone else to their rules and then use their doctrines (which I just mentioned above) to justify their own hypocrisy and double standards. They only apply these doctrines in practice to themselves, not to those who they bully within their own churches. Satan has turned them into narcissistic sociopaths (mentally abnormal people- aka antisocial personality disorder) through their carnal minded doctrines. Instead of more churches among them rising up, they need to do the Christian community a favor and dissolve as soon as possible."
Tongues are not the only thing which carnal minded Christians teach to be a mandatory indicator of spirituality. Carnal minded Christians also make wealth/worldly success as an indicator of spirituality/favor from God. 1 Timothy 6:5 warns true Christians regarding carnal minded Christians/false teachers. To such people, a show of fake/superficial godliness is a way to become wealthy (I believe many false teachers/pastors have found a business/income through such deception). They can use this as a means of deceiving the poor to think that they are not blessed/wealthy enough compared to others because they are not spiritual enough. Such false teachers can then tell these people to give them money (and equate that to giving money for the Lord's work) and thereby earn an income through such deception. The messages of such false teachers which promote carnal minded Christianity/licentiousness also cater to the itching ears of carnal minded people who are ready to financially support them. The Bible further reveals how such carnal minded Christians (impostors within Christianity), reject God's power that could truly make them godly (refer to 2 Timothy 3:5). The Bible teaches (refer to 1 Timothy 6:6-8) that "true godliness with contentment is itself great wealth and to be content if we have enough food and clothing." Satan tries to distract believers (especially the poor among Christians) regarding that truth through false teachers who instead promote carnality/pursuit of wealth. Their goal is to brainwash people and instill inadequacies in people by making them feel that they lack certain things when comparing themselves to those who are wealthier than them. This is how they instill the sin of covetousness in people. They can also destroy people's faith in God by making them feel inadequate and thereby make them doubt and grumble against God for showing favoritism to people around them. Jesus gave a warning to such carnal minded people who cause others to sin- refer to Matthew 18:6-9. Many carnal minded Christians think that they have favor from God (despite being evil) because they are materially blessed/wealthy. The Bible states such people only deceive themselves and others into their eternal destruction.
2 Timothy 3:13 (NLT):
But evil people and impostors will flourish. They will deceive others and will themselves be deceived.
1 Timothy 6:5 (NLT):
These people always cause trouble. Their minds are corrupt, and they have turned their backs on the truth. To them, a show of godliness is just a way to become wealthy.
2 Timothy 3:5 (NLT):
They will act religious, but they will reject the power that could make them godly. Stay away from people like that!
2 Peter 2:1-3 (NLT):
But there were also false prophets in Israel, just as there will be false teachers among you. They will cleverly teach destructive heresies and even deny the Master who bought them. In this way, they will bring sudden destruction on themselves. 2 Many will follow their evil teaching and shameful immorality. And because of these teachers, the way of truth will be slandered. 3 In their greed they will make up clever lies to get hold of your money. But God condemned them long ago, and their destruction will not be delayed.
I've made a short Google Plus post on this also (refer to If you are not wealthy, you still have the opportunity during this time to be spiritually wealthy by being rich in your faith in God).
The real indicator/identity of a Christian is the fruit of the Spirit (which includes godly love). Refer to 1 John 3:14-19 and Galatians 5:22-23.