qui bene amat, bene castigat

Etymology
lit. 'he who loves well, castigates well'.

This form of the phrase is likely a calque from. Similar phrases are found in Latin texts:

Proverb

 * 1) spare the rod and spoil the child

Usage notes

 * This proverb, which has been used especially as a recurrent theme in education, can have the following two distinct interpretations:
 * 1) he who loves will not hesitate to chastise, in the interest of the one being loved
 * 2) only he who loves will be able to exercise the punishment in a sensible way.