The Bible is replete with exhortations about discipline, and examples of stiff discipline allowed or brought by the Lord, in both Old and New Testaments. Some examples:

"Folly is bound up in the heart of a boy, but the rod of discipline drives it far away." - Proverbs 22.12

"Do not withhold discipline from your children; if you beat them with a rod, they will not die. If you beat them with the rod, you will save their lives from Sheol." - Proverbs 23.14-15

"The rod and reproof give wisdom." - Proverbs 29:15

"Discipline your children and they will give you rest; they will give delight to your heart." - Proverbs 29:17

"I will be his father, and he shall be my son: if he commit iniquity, I will chasten him with the rod of men, and with the stripes of the children of men." - 2 Samuel 7:14

"On the lips of one who has understanding wisdom is found, but a rod is for the back of one who lacks sense." Proverbs 10:27

"Those who spare the rod hate their children, but those who love them are diligent to discipline them." - Proverbs 13:24

"The Lord disciplines those whom he loves, and scourges every child whom he accepts." - Hebrews 12:6