Read Exodus 22
These are some very basic and sensible laws. Looking at the part of a thief and the sun coming up.
I think what is meant here is that if someone has broken in, and it's dark, then one would not know it they are armed or not and would not recognize them. Offensive action is acceptable, but if the thief can be seen and identified, then there is no need to strike, the matter is for the local law.
No workout today, rest.