"Strengthen Your Weak Knees

In your struggle against sin you have not yet resisted to the point of shedding your blood. And have you forgotten the exhortation that addresses you as sons?
“My son, do not regard lightly the discipline of the Lord,
nor be weary when reproved by him.
For the Lord disciplines the one he loves,
and chastises every son whom he receives.”
It is for discipline that you have to endure. God is treating you as sons. For what son is there whom his father does not discipline? If you are left without discipline, in which all have participated, then you are illegitimate children and not sons. Besides this, we have had earthly fathers who disciplined us and we respected them. Shall we not much more be subject to the Father of spirits and live? For they disciplined us for a short time as it seemed best to them, but he disciplines us for our good, that we may share his holiness. For the moment all discipline seems painful rather than pleasant, but later it yields the peaceful fruit of righteousness to those who have been trained by it. Therefore lift your drooping hands and strengthen your weak knees," (Heb 12:4-12).
In his outstanding book How Long O Lord? D.A. Carson comments on this passage:
1. The context shows that the discipline the author has in mind is designed to help Christians combat sin.
2. The author designates the cited passage from Proverbs as a "word of encouragement."
3. This discipline is for our good.
4. This is so much a part of God's way with his people that if any live without God's discipline in their lives their status as the children of God is called into question.
5. No discipline seems pleasant at the time but painful.