God finally, after Abraham and Sarah are past the age of childbearing, gives a son to them. Isaac grows and after many years, God instructs Abraham to offer him as a sacrifice.
I've seen friends from time to time "fast" from social media, or people like to give up certain things during Lent. This is not the same thing! God wants to test Abraham and see if Isaac has become an idol to Abraham. While Facebook or chocolate can be unhealthy, and might be idols in certain people's lives, this is much different. Abraham isn't taking "time off" from Isaac. This is a man going to place all his hopes and dreams and future and his only child on an alter to be slain, even by his own hand! He is not making due without something, that may be a minor inconvenience, at best. He is laying it all down before God and saying, there is nothing standing in Your rightful place, You have it all! While there are things God wants us to "fast" from, God is not calling Abraham to fast, He's calling him to sacrifice.
The thing that amazes me about Abraham in this passage, is how he is immediately obedient! He doesn't wait a few days to see if God will change his mind or wait until a more convenient time in his life. God says go, Abraham leaves.
The beauty part of this story is that God doesn't ask something of us that He is unwilling to do himself. Years later it will be His son on a hill, but this time the Father will not hold back the knife. Isaac was a gift from God to Abraham. What gifts from God have become idols to you? Like Abraham you may not need to sacrifice them, but are you willing to?