Not exceed: it seems not superstition, but prudent caution, when the Jews would not exceed thirty-nine stripes, 2 Corinthians 11:24, lest through mistake or forgetfulness or eagerness they should go beyond their bounds, which they were commanded to keep, but they were not obliged to go to the utmost extent of them. Thy brother, who, though faulty and chastised, yet still is thy brother by nation, and probably by religion too. Should seem vile unto thee, i.e. should be made contemptible to his brethren, either by this cruel usage of him, as if he were a slave or brute beast; or by the deformity or infirmity of body which excessive beating might produce.
Related Commentaries of Deuteronomy 25:3
Deuteronomy 25:3
3 Forty stripes he may give him, and not exceed: lest, if he should exceed, and beat him above these with many stripes, then thy brother should seem vile unto thee.