Psalms 103:1

Bless the Lord - He calls on his soul, and all its faculties and powers, to magnify God for his mercies. Under such a weight of obligation the lips can do little; the soul and all its powers must be engaged.

Bless the Lord, O my soul - The word "bless," as applied to God, means to praise, implying always a strong affection for him as well as a sense of gratitude. As used with reference to people, the word implies a "wish" that they may be blessed or happy, accompanied often with a prayer that they may be so. Such is the purport of the "blessing" addressed to a congregation of worshippers. Compare Numbers 6:23-27. The word "soul" here is equivalent to mind or heart: my mental and moral powers, as capable of understanding and appreciating his favors. The soul of man was "made" to praise and bless God; to enjoy his friendship; to delight in his favor; to contemplate his perfections. It can never be employed in a more appropriate or a more elevated act than when engaged in his praise.

And all that is within me ... - All my powers and faculties; all that can be employed in his praise: the heart, the will, the affections, the emotions. The idea is, that God is worthy of all the praise and adoration which the entire man can render. No one of his faculties or powers should be exempt from the duty and the privilege of praise.