Isaiah 25:1 O Lord, thou art my God; I will exalt thee, I will praise thy name; for thou hast done wonderful things; thy counsels of old are faithfulness and truth.
God not only knows everything we say but everything we think and feel, so why should we exalt and praise Him?
If you think that the primary reason is so that others will hear our witness, be not surprised if I tell you that is the secondary reason. The primary reason is because of our human nature. We are weak, beggarly, flighty, forgetful and easily distracted.
Look how easy it is to fall off the wagon of determination. Will power is not our strong suit. We are creatures of habit however and if we can get in the habit of exalting and praising Him, then the only danger we run is insincerity.
Being sincere in exaltation and praise is neither a matter of will nor habit, it is a matter of character. Be that person who is the new creation which God has transformed. The new creature with the new nature, who is not outwardly appearing but inwardly real.
Ephesians 3:16-19 That he would grant you, according to the riches of his glory, to be strengthened with might by his Spirit in the inner man; That Christ may dwell in your hearts by faith; that ye, being rooted and grounded in love, May be able to comprehend with all saints what is the breadth, and length, and depth, and height; And to know the love of Christ, which passeth knowledge, that ye might be filled with all the fulness of God.
Would you rather be filled with God or full of yourself?
That is not a mere matter of determination, it takes humility and submission. God will do in you everything required to conform you if you surrender to His will.
Ephesians 6:6 Not with eyeservice, as menpleasers; but as the servants of Christ, doing the will of God from the heart;