1 Corinthians 14:1-2
1. Pursue love, yet desire earnestly spiritual gifts, but especially that you may prophesy. 2 For one who speaks in a tongue does not speak to men but to God; for no one understands, but in his spirit he speaks mysteries.
What is the mysteries it talks about?
1 Corinthians 15:51 - 51 Behold, I tell you a mystery; we will not all sleep, but we will all be changed,
Acts 2:2-13
2 And suddenly there came from heaven a noise like a violent rushing wind, and it filled the whole house where they were sitting. 3 And there appeared to them tongues as of fire distributing themselves, and they rested on each one of them. 4 And they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit was giving them utterance.
5 Now there were Jews living in Jerusalem, devout men from every nation under heaven. 6 And when this sound occurred, the crowd came together, and were bewildered because each one of them was hearing them speak in his own language. 7 They were amazed and astonished, saying, “Why, are not all these who are speaking Galileans? 8 And how is it that we each hear them in our own language to which we were born? 9 Parthians and Medes and Elamites, and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, 10 Phrygia and Pamphylia, Egypt and the districts of Libya around Cyrene, and visitors from Rome, both Jews and proselytes, 11 Cretans and Arabs—we hear them in our own tongues speaking of the mighty deeds of God.” 12 And they all continued in amazement and great perplexity, saying to one another, “What does this mean?” 13 But others were mocking and saying, “They are full of sweet wine.”
Acts 10:45-46
45 All the circumcised believers who came with Peter were amazed, because the gift of the Holy Spirit had been poured out on the Gentiles also. 46 For they were hearing them speaking with tongues and exalting God. Then Peter answered, 47 “Surely no one can refuse the water for these to be baptized who have received the Holy Spirit just as we did, can he?”
1 Corinthians 12:4-10, 28
4 Now there are varieties of gifts, but the same Spirit. 5 And there are varieties of ministries, and the same Lord. 6 There are varieties of effects, but the same God who works all things in all persons. 7 But to each one is given the manifestation of the Spirit for the common good. 8 For to one is given the word of wisdom through the Spirit, and to another the word of knowledge according to the same Spirit; 9 to another faith by the same Spirit, and to another gifts of healing by the one Spirit, 10 and to another the effecting of miracles, and to another prophecy, and to another the distinguishing of spirits, to another various kinds of tongues, and to another the interpretation of tongues.
28 And God has appointed in the church, first apostles, second prophets, third teachers, then miracles, then gifts of healings, helps, administrations, various kinds of tongues.
1 Corinthians 14:9-10
9 So also you, unless you utter by the tongue speech that is clear, how will it be known what is spoken? For you will be speaking into the air. 10 There are, perhaps, a great many kinds of languages in the world, and no kind is without meaning.