Psalm 103:1

Bless the Lord, O my soul
His better part, his soul, which comes immediately from God, and returns to him, which is immaterial and immortal, and of more worth than the world: God is to be served with the best we have; as with the best of our substance, so with the best of our persons; and it is the heart, or soul, which he requires to be given him; and such service as is performed with the soul or spirit is most agreeable to him; he being a Spirit, and therefore must be worshipped in spirit and in truth: unless the spirit or soul of a man, is engaged in the service of God, it is of little avail; for bodily exercise profiteth not; preaching, hearing, praying, and praising, should be both with the spirit, and with the understanding: here the psalmist calls upon his soul to "bless" the Lord; not by invoking or conferring a blessing on him, which as it is impossible to be done, so he stands in no need of it, being God, all sufficient, and blessed for evermore; but by proclaiming and congratulating his blessedness, and by giving him thanks for all mercies, spiritual and temporal:

and all that is within me,
bless his holy name; meaning not only all within his body, his heart, reins, lungs but all within his soul, all the powers and faculties of it; his understanding, will, affections, and judgment; and all the grace that was wrought in him, faith, hope, love, joy, and the like; these he would have all concerned and employed in praising the name of the Lord; which is exalted above all blessing and praise; is great and glorious in all the earth, by reason of his works wrought, and blessings of goodness bestowed; and which appears to be holy in them all, as it does in the works of creation, providence, and redemption; at the remembrance of which holiness thanks should be given; for he that is glorious in holiness is fearful in praises, ( Psalms 97:12 ) ( Exodus 15:11 ) .