Adam Clarke on Psalms 119:57

Thou art my portion, O Lord - From the fifty-seventh to the sixtieth verse may be seen the progress of the work of grace on the human heart, from the first dawn of heavenly light till the soul is filled with the fullness of God. But as I consider this Psalm as notes selected from diaries of past experience, formed at different times; and that the author has been obliged, for the support of his acrostic plan, to interchange circumstances, putting that sometimes behind which in the order of grace comes before; because, to put it in its right place, the letters would not accord with the alphabetical arrangement; I shall therefore follow what I conceive to be its order in the connection of grace, and not in the order in which the words are here laid down.