When God made the world He built into it a certain rhythm.
For example, in the beginning...
"God called the light day, and the darkness He called night. And there was evening and there was morning, one day" (Gen.1:5).
So, it's according to this rhythm we live our lives...
We have a day and go to bed dead tired, and on the next day He raises us up with new energy to serve Him.
This daily pattern is also a picture of what Jesus does for us through His death and resurrection...
With each new day reminding us it's in Him we live out the purpose He has for us...
... and without Him our daily rhythm is incomplete.