There are many scriptures verses that tell us to be careful what we do and say as born again believers...
My favourite has to be John 15, as it includes the warnings of being pruned out, cast out, becoming withered and being destroyed, but it also encourages us, in a most wonderful way, to remain in Christ, Abide in Christ, and in doing so, herein is the Father Glorified.
A small selection
Psalm 34:13 Keep thy tongue from evil, and thy lips from speaking guile.
Psalm 52:4 Thou lovest all devouring words, O thou deceitful tongue.
Psalm 1120:2 Deliver my soul, O Lord, from lying lips, and from a deceitful tongue.
Job 12:11 Doth not the ear try words? and the mouth taste his meat?
The Word has 'a lot' to say about the tongue... it can be used against God, it can cut us off from God, it can be used to accept God and to Glorify God in so many ways. The tongue can be used to preach, to repent, it can even be as a double edged sword.
But we must always be careful as born again believers to use it to bring Glory to God through Jesus Christ our Lord.
1 Peter 3:10 For he that will love life, and see good days, let him refrain his tongue from evil, and his lips that they speak no guile: