Ten Reason Why Every Believer Should Speak in Tongues 

1. Tongues the initial sign of a supernatural evidence of the Spirit’s indwelling  

Acts 2:4 And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.

2. Tongues are used for Spiritual Edification     

   1 Corinthians 14:4 He that speaketh in an unknown tongue edifieth himself

3. Tongues Remind Us of the Spirit’s Indwelling Presence  

John 14:16-17  And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;   17 Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.

4. Praying in Tongues is Praying in Line with God’s Perfect Will     

Romans 8:26-27   Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered.    27 And he that searcheth the hearts knoweth what is the mind of the Spirit, because he maketh intercession for the saints according to the will of God.

5. Praying in Tongues Stimulate Faith    

Jude 20  But ye, beloved, building up yourselves on your most holy faith, praying in the Holy Ghost,

6. Speaking in Tongues is a Means of Keeping Fee from Worldly Contamination           

 1 Corinthians 14:28   But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God.

7. Praying in Tongues Enables Us to Pray for the Unknown 

1 Corinthians 14:2  For he that speaketh in an unknown tongue speaketh not unto men, but unto God: for no man understandeth him; howbeit in the spirit he speaketh mysteries.

8. Praying in Tongues Gives Spiritual Refreshing                                                                

Isaiah 28:11-12   For with stammering lips and another tongue will he speak to this people. 12 To whom he said, This is the rest wherewith ye may cause the weary to rest; and this is the refreshing: yet they would not hear.

9. Tongues is for Giving Thanks                                                                                                         

1 Corinthians 14:15-17  What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.  16 Else when thou shalt bless with the spirit, how shall he that occupieth the room of the unlearned say Amen at thy giving of thanks, seeing he understandeth not what thou sayest?  17 For thou verily givest thanks well, but the other is not edified.

10. Speaking in Tongues Brings the Tongue Under Subjection                                       

James 3:8  But the tongue can no man tame; it is an unruly evil, full of deadly poison.

Resource 

Why Tongues by Kenneth E. Hagin,  Rhema Bible Church © 1975 Kenneth Hagin Ministries Ministries