Ibn Ezra on Isaiah
I, the Lord, have called thee, etc. The Lord in these words addresses the prophet upon his own concerns.
Rashi on Isaiah
and I formed you Heb. וְאֶצָּרְךָ. When I formed you (כְּשֶׁיְצַרְתִּיךָ), this was My thought, that you return My people to My covenant and to enlighten them.