Deuteronomy 25:3
He may receive no more than forty lashes, lest your brother be beaten any more than that and be degraded in your sight.
What it says
The lashes must not exceed forty, so the guilty man is not degraded in the sight of his brothers.
What it is doing
It limits punishment to preserve the offender's human standing.
In context
1If there is a dispute between men, they are to go to court to be judged, so that the innocent may be acquitted and the guilty condemned. 2If the guilty man deserves to be beaten, the judge shall have him lie down and be flogged in his presence with the number of lashes his crime warrants. 3He may receive no more than forty lashes, lest your brother be beaten any more than that and be degraded in your sight. 4Do not muzzle an ox while it is treading out the grain.