John Calvin Commentary Psalms 119:173

"Let thy hand be ready to help me; For I have chosen thy precepts." — Psalms 119:173 (ASV)

Let your hand be to succor me. As he had devoted himself to the doctrine of the law, David requests that God's hand may be stretched out for his aid. Furthermore, by these words he declares that those who submit themselves to God to be governed by His word continually need His help.

The more sincerely any individual strives to be a good man, the more numerous are the ways in which Satan troubles him, and the more are enemies multiplied who harass him on all sides. But when God sees those who once embraced the truth of His word remaining steadfast in their resolution, He is all the more inclined to aid them.

By the word choose in the second clause, the psalmist expressed that nothing hindered him from devoting himself to the law of God. No one will apply themselves to loving the law without a great struggle, since everyone's thoughts are drawn away to various other things by the sinful desires of the flesh.

This choosing, then, shows that God's children do not desire heavenly doctrine above all things out of ignorance or rash zeal; rather, because they share in the mental flexibility common to all people and experience the various impulses of the flesh, they deliberately subdue their minds to obey God.