but I fail to see how he could have learned anything good or godly by being rejected by his parents.
I don't think anyone here on this thread is suggesting or directing parents to reject or banish their wayward children. Far from it.
My son is a amphetamine drug user and does crime to support his habit. Occasionally he needs to escape and come home for a while.
I love him immensely (and he knows it and milks it). BUT I still go to Revival meetings and invite him to come along. I still openly read my Bible.
I remind him that he has no blessings in his life because of his path in life. He grumbles and tries to convince himself that all is against him
through bad luck. I pray in the Spirit and he can hear me from other rooms in the house. I post up testimonies on the fridge from people
who have been saved and converted by the true gospel from their previous druggy & criminal lifestyle for him to read.
I love him. I care for him (he's 24 yo now). BUT I let him see the difference between my commitment and faith in Jesus and his righteousness,
as opposed to his choices. Without lecturing him or scolding him. Without holding back on any practical assistance that he always seems to need.
BUT he knows that his dad is a dinky di Christian who practices what he preaches. Love through expressing the gospel.
Luke 15:
20 And he arose, and came to his father. But when he was yet a great way off, his father saw him, and had compassion, and ran, and fell on his neck, and kissed him.
21 And the son said unto him, Father, I have sinned against heaven, and in thy sight, and am no more worthy to be called thy son.
22 But the father said to his servants, Bring forth the best robe, and put it on him; and put a ring on his hand, and shoes on his feet:
32 It was meet that we should make merry, and be glad: for this thy brother was dead, and is alive again; and was lost, and is found.
In order for this to happen then a sinner needs to come back to their Father in heaven - and how does one do this?
John 14:
5 Thomas saith unto him, Lord, we know not whither thou goest; and how can we know the way?
6 Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.