Hebrews 12:11

Now, at the time, discipline seems to be a matter not for joy, but for grief; yet it afterwards yields to those who have passed through its training a result full of peace--namely, righteousness.

Matthew 10:37

Any one who loves father or mother more than me is not worthy of me, and any one who 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
Any one who loves father or mother more than me is not worthy of me, and any one who loves son or daughter more than me is not worthy of me;
Hebrews 12:11
Now, at the time, discipline seems to be a matter not for joy, but for grief; yet it afterwards yields to those who have passed through its training a result full of peace--namely, righteousness.