This may not have the same meaning for God as it has for me. I mean, it's not like He sleeps at night (at all!!!) and wakes up to a renewed sense of grace. It is us who require that sleep--that rest--from all of life's chaos. Somehow, when we curl up on our pillows at night after a stressful day and we pray that tomorrow will be better, we know it will be because 1)it's a new day, and 2) God's mercy and grace are refreshing (again!).
It is of the LORD's mercies that we are not consumed, because his compassions fail not. They are new every morning: great is thy faithfulness. The LORD is my portion, saith my soul; therefore will I hope in him.