I have become convinced that the penultimate phrase in this text should be translated, "I live by the faith of the Son of God." The emphasis of the verse is not on OUR faith in Christ, but on CHRIST'S faith (or faithfulness) in loving us and sacrificing his life on our behalf. We live by his faith and faithfulness.
Today's Advent psalm, Psalm 31, is an exposition of this truth. It describes the Faith of the King. Here are the first five verses:
In you, O Lord, I seek refuge;Jesus found in King David's words such a statement of his own faith in his Father that he used them when he was dying on the cross.
do not let me ever be put to shame;
in your righteousness deliver me.
Incline your ear to me;
rescue me speedily.
Be a rock of refuge for me,
a strong fortress to save me.
You are indeed my rock and my fortress;
for your name’s sake lead me and guide me,
take me out of the net that is hidden for me,
for you are my refuge.
Into your hand I commit my spirit;
you have redeemed me, O Lord, faithful God.245
It was now about noon, and darkness came over the whole land until three in the afternoon, while the sun’s light failed; and the curtain of the temple was torn in two. Then Jesus, crying with a loud voice, said, ‘Father, into your hands I commend my spirit.’ Having said this, he breathed his last. (Luke 23.44-46)This is why our Savior came into the world at Christmas. He came to live by faith in his Father and to be faithful to his mission, which meant loving us and giving himself for us.
We live by the faith of the Son of God.