Darkness = Absence of light.
Rest = Absence of work?
Well, the above equality may not hold. If we don't work, how will we know what rest is. Also, for some workaholics, they may feel lost and uneasy without work.
Work had been created by God right from the beginning, and we should do whatever God work give us to with pride, as it is a way of honouring Him. That said, I'm now motivated to honour God as a student, in other words, I will study hard. Hopefully, I can truly be a testimony for God, both through the process as well as with the end results.

"And whatever you do, whether in word or deed, do it all in the name of the Lord Jesus, giving thanks to God the Father through him." Colossians 3: 17