养痈遗患

lit. to foster an ulcer and bequeath a calamity (idiom); tolerating budding evil can only lead to disaster; to cherish a viper in one's bosom

Rear a tiger and court disaster. (idiom); fig. if you're too lenient with sb, he will damage you later; to cherish a snake in one's bosom

lit. to nurture a tiger invites calamity; fig. to indulge one's enemy is asking for trouble (idiom)

Rear a tiger and court disaster. (idiom); fig. if you're too lenient with sb, he will damage you later; to cherish a snake in one's bosom

to tolerate is to abet

to tolerate is to nurture an evildoer (idiom); spare the rod and spoil the child