At this very moment, if Abraham had a trace of complaint, even though he might have killed his son, the offering of his son would have been rejected by God. So many times we do good things, but if our heart is not there, the deeds do not blossom in the glory of God. If Abraham had complained, the purpose of God's glory would not have been achieved. But when Abraham lifted his knife, there was no hesitation. God will respond to man's heart, not to his deed.
Deed is the manifestation of the heart.
If we do things without the right heart, it is not acceptable to God. With our heart we can separate ourselves from Satan. Satan's temptation to Jesus was the first showdown between Jesus and Satan. The Bible says that Satan entered the heart of Judas. He wanted to make the hearts of the people rebellious.