What does it mean to return to God?
Is not "the entire world filled with His glory"?
If man is always in the presence of God, how can he return to Him?
Yet, to quote the prophet, man can be in a state in which "they have turned their backs to Me and do not face Me.”
When a person turns his back on someone, he might be in close proximity to that person-they might even be pressed against each other back to back-yet they are as far apart from each other as they can possibly be.
Teshuvah, then, is a shift in orientation: a person turning to God, after having spurned Him.
–Rabbi Adin Steinsaltz
From Opening the Tanya by Rabbi Adin Steinsaltz