Psalms 66:17

I cried unto him with my mouth, and he was extolled with my tongue.

The verse portrays calling upon God aloud with the mouth while honoring and lifting Him up with the tongue, so that prayer and praise are joined together. That crying and extolling is declaring from the soul what He has done for the soul, and inviting all who fear God to come and hear it. Such praise springs from a full heart enjoying the love of God within, with praise and thanksgiving coming forth as the fruit of the lips from the good treasure inside.

This is the privilege and proper language of every soul, belonging to those who die to self, which is life, who do not give up the interests of the soul, and who show the blessed light to all with whom they associate. This spoken testimony is how the message of truth goes forward like a burning lamp, so that God's way is known upon the earth and His saving health among all nations. Human lips and pens must do this proclaiming to bring belief and obedience to all His commandments, since nature alone only declares a living God and angels are sent only to help human beings proclaim to a perishing world.

Sincere prayer must come from the heart and not be mere outward lip-service. Cherishing iniquity in the heart while praying prevents the Lord from hearing and causes the prayer to be rejected as unaccepted.