As a father has compassion on his children, so the LORD has compassion on those who fear him. Psalm 103:13
What is David telling us here? He is telling us that a godly “father” disciples his children not out of malice, but because he loves them. And God demonstrates mercy and compassion toward his children through forgiveness of sin and blessing, in spite of their weakness. The writer of Hebrews puts it this way in Hebrews 12:3-13:
For consider him who endured such hostility from sinners against himself, so that you won’t grow weary and give up. In struggling against sin, you have not yet resisted to the point of shedding your blood. And you have forgotten the exhortation that addresses you as sons:
My son, do not take the Lord’s discipline lightly
or lose heart when you are reproved by him,
for the Lord disciplines the one he loves
and punishes every son he receives.
Endure suffering as discipline: God is dealing with you as sons. For what son is there that a father does not discipline? But if you are without discipline — which all receive — then you are illegitimate children and not sons. Furthermore, we had human fathers discipline us, and we respected them. Shouldn’t we submit even more to the Father of spirits and live? For they disciplined us for a short time based on what seemed good to them, but he does it for our benefit, so that we can share his holiness. No discipline seems enjoyable at the time, but painful. Later on, however, it yields the peaceful fruit of righteousness to those who have been trained by it.
Therefore, strengthen your tired hands and weakened knees, and make straight paths for your feet, so that what is lame may not be dislocated but healed instead.
This familial language appears throughout the book of Hebrews. The First Person of the Trinity is God the Father, and the Second Person of the Trinity is God the Son. The Son became a human being in order to unite himself with his believing brothers and sisters. The Son can then bring believers into the presence of the Father, who will discipline them as “sons”. The writer of Hebrews is citing Proverbs 3:11-12, when he argues the because believers are sons of God, they have a superior source of comfort. We are more than mere servants, God addresses us as sons. And yet, a father displays his love for his sons by disciplining them. Just as we have accepted discipline from our “human fathers”, so too should we receive discipline from the “Father of spirits”. God does not discipline his sons to harm them, but to bless them. The benefit of the Father’s discipline is fellowship in his “holiness” and bearing the “peaceful fruit of righteousness”.
Both David and the writer of Hebrews are saying the exact same thing. They are both saying that our physical fathers discipline us in order to help us grow and not out of a need to harm us or to be cruel. And our Heavenly Father does the exact same thing. God the Father disciplines us in order to help us grow spiritually, and not to harm us and not just to punish us. And when we accept that and recognize that we can us God’s discipline for its intended purpose.