Why Muhammad accept the concept of Abraham sacrificing his only son but rejected the concept of GOD?

Question

sacrificing his only incarnated son Jesus Christ

Answer 1

1> We reject the concept of original sin, so there would be no sacrifice,
2> To us Jesus is not God, Jesus is a man, a prophet,

Simple as that.

Answer 2

Muhammad (PBUH) received Abraham's stories from God and they are written down in the Recital (Qur'an). He is The same God who reveled to Muhammad (PBUH) that Jesus (PBUH) is NOT the "son of God", but rather, the son of Mary (PBUH).

Incidentally, it's also the same God who created Jesus (PBUH) as he had created Adam (PBUH) before him.