Translation:

45. If Allah were to punish men according to what they deserve He would not leave on the back of the (earth) a single living creature: but He gives them respite for a stated Term: when their Term expires verily Allah has in his sight all His servants.

Notes (Tafseer)

3940. Cf. xvi. 61. There would be no salvation for any of us if we went merely on our deserts. It is Allah's mercy that saves us and helps us to a better and better life until we attain the goal of our existence.

3941. A single living creature. This may refer to man, the living crawling creature, with so many possibilities and yet so many weaknesses. But it may mean all creatures literally, as the life of this planet more or less centres round the life of man. He has been given dominion on this earth, and in his state of purity he is Allah's vicegerent.

3942. Has in His sight all creatures: i.e., to deal with, according to His laws of Forbearance, Mercy and Justice: see n. 3937 above. The respite does not mean that any one escapes Hiis vigilant eye. All will be dealt with according to their deeds, with justice tempered with Mercy.