Deuteronomy 25:2; Deuteronomy 25:3

2 then if the guilty man deserves to be beaten, the judge shall cause him to lie down and be beaten in his presence with a number of stripes in proportion to his offense.

3 Forty stripes may be given him, but not more, lest, if one should go on to beat him with more stripes than these, your brother be degraded in your sight.