Albert Barnes Commentary Psalms 116:7

"Return unto thy rest, O my soul; For Jehovah hath dealt bountifully with thee." — Psalms 116:7 (ASV)

Return unto thy rest, O my soul - Luther, “Be you again joyful, O my soul.” The meaning seems to be, “Return to your former tranquility and calmness; your former freedom from fear and anxiety.”

He had passed through a season of great danger. His soul had been agitated and terrified. That danger was now over, and he calls upon his soul to resume its former tranquility, calmness, peace, and freedom from alarm. The word does not refer to God considered as the “rest” of the soul, but to what the mind of the psalmist had been, and might now be again.

For the Lord hath dealt bountifully with thee - See the notes at Psalms 13:6.