John Calvin Commentary Psalms 18:3

"I will call upon Jehovah, who is worthy to be praised: So shall I be saved from mine enemies." — Psalms 18:3 (ASV)

I will call upon the praised Jehovah. Calling upon God, as has been observed elsewhere, frequently includes the whole of His service; but as the effect or fruit of prayer is particularly mentioned in what follows, this phrase in the present passage, I have no doubt, signifies turning to God for protection and asking by prayer for deliverance from Him.

David, having said in the second verse that he trusted in God, now adds this as evidence of his trust; for everyone who confides in God will earnestly seek His aid in time of need. He therefore declares that he will be saved and prove victorious over all his enemies because he will turn to God for help.

He calls God the praised Jehovah, not only to suggest that He is worthy of being praised, as almost all interpreters explain it, but also to point out that when he came to the throne of grace, his prayers would be mingled and interwoven with praises. The context of the passage seems to require that it be understood as meaning that, giving thanks to God for the benefits he has received from Him in times past, he will ask His assistance by renewed supplications. And certainly, no one will ever invoke God in prayer freely and frankly unless he animates and encourages himself by the remembrance of the grace of God. Accordingly, Paul, in Philippians 4:6, exhorts the faithful:

in every thing by prayer and supplication with thanksgiving, to make their requests known unto God (Philippians 4:6).

...and to unload their cares, as it were, into His bosom. All those whose prayers are not accompanied with the praises of God can be accused of clamoring and complaining against Him when engaged in that solemn exercise.