Proverbs 23:13-14Spanking a child's bottom is not physical violence. For me, it takes a great deal more strength to carry through with discipline in the form of a spanking rather than consistenly telling a child to "stop that or else...", which get's no results. Spanking is not necessarily to be done as the sole form of punishment, but the threat of a quick effective consequence is key for getting a child to readily obey a parent. The real temptation is to NOT spank or carry through with a punishment that we really don't want to inflict on our children.
(13) Do not hold back discipline from the child, Although you strike him with the rod, he will not die.
(14) You shall strike him with the rod And rescue his soul from Sheol.
Proverbs 13:24
(24) He who withholds his rod hates his son, But he who loves him disciplines him diligently.
If corporal punishment is involved at the age of 13 - the parent failed the child at least 4 years earlier.