Hebrews 12:11

All chastening, indeed, for the present seems not to be joyous, but grievous; but afterward it yields the peaceful fruit of righteousness to those who have been trained thereby.

Matthew 10:37

"He that loves father or mother more than Me, is not worthy of Me; and he that loves son or daughter more than Me, is not worthy 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 loves father or mother more than Me, is not worthy of Me; and he that loves son or daughter more than Me, is not worthy of Me.
Hebrews 12:11
All chastening, indeed, for the present seems not to be joyous, but grievous; but afterward it yields the peaceful fruit of righteousness to those who have been trained thereby.