Adam Clarke on Psalms 119:6

Then shall I not be ashamed - Every act of transgression in the wicked man tends to harden his heart; and render it callous. If a man who fears God is so unhappy as to fall into sin, his conscience reproaches him, and he is ashamed before God and man. This is a full proof that God's Spirit has not utterly departed from him, and that he may repent, believe and be healed.

Unto all thy commandments - God requires universal obedience, and all things are possible to him whom Christ strengthens; and all things are possible to him that believes. Allow that any of God's commandments may be transgressed, and we shall soon have the whole decalogue set aside.