At thy right hand there are pleasures for evermore (Ps. 16: 11)
He that spareth his rod hateth his son: But he that loveth him chasteneth him betimes (KJV).
Proverbs 13:24
He who spares his rod hates his son, But he who loves him disciplines him promptly (NKJV).
Hatred can be sentimental, and within tangled family situations, it frequently is. To love someone is to treat them lawfully, from the heart. To hate someone is to treat them unlawfully, whether or not you have certain soppy emotions going on while you do it.
Scripture says that sons require corporal punishment, as the occasion requires. Some Christians have reacted against this teaching (or, more likely, have reacted against an ungodly misapplication of this) and have argued for childhood training that does not involve spanking. The emotions that seem to require this may be soft, tender, and kind, but Scripture says that at the end of the day it all reduces to hatred. If someone grew up under cruel or inept corporal punishment, that is certainly sad, but it doesn’t change what Scripture says here.
So the Bible teaches that if a father refuses to discipline his child, this is equivalent to disowning that child—treating him as an illegitimate bastard. “But if ye be without chastisement, whereof all are partakers, then are ye bastards, and not sons” (Heb. 12:8). God corrects us, and He is a true Father. So we also should correct our children, and thus imitate the true Father as we do. God does not disown us through lack of discipline, and this means that we should not disown our own children through lack of discipline.
Some in the anti-spanking contingent might want to say that this verse is talking about a rod for the back, not a spanking spoon for the bum, and that it is not talking about spanking at all. But this is an objection that proves too much. If it is legitimate to beat a recalcitrant teenagers with a rod, according to their reading, how much more would it be appropriate to spank a two-year-old with a spoon, thus averting the drastic punishment over a decade later?