Hebrews 12:11

'tis true, all correction at first is far from appearing agreeable, yet afterward it produces the agreeable fruits of virtue in those who are exercised thereby.

Matthew 10:37

he that loveth father or mother more than me, is unworthy of me: he that loveth son or daughter more than me, is unworthy of me.

Treasury of Scripture Knowledge

Summary

And the thing was very grievous in Abraham's sight because of his son.

Bible References

Because

Matthew 10:37
he that loveth father or mother more than me, is unworthy of me: he that loveth son or daughter more than me, is unworthy of me.
Hebrews 12:11
'tis true, all correction at first is far from appearing agreeable, yet afterward it produces the agreeable fruits of virtue in those who are exercised thereby.