[Hope]

Muslims and Christians are like brothers quarrelling and fighting at home lah!  Because Isaac was the promised son but Ishmael was rejected but both were Abraham's sons lah!

Yes,We are brothers. However Muslim don’t differentiate between Ishmael and Issac.It is the problem of the Jews which Christian also supporting blindly.
Are you following the religion of Abraham, Isaac, Jacob? No. Because They were not Jewish or Christian.Then how come you are attached to Isaac ?

O People of the Scripture, why do you argue about Abraham while the Torahand the Gospel were not revealed until after him? Then will you not reason?”Quran 3:65

“Abraham was neither a Jew nor a Christian, but he was one inclining toward truth, a Muslim [submitting to Allah]. And he was not of the polytheists.”Quran 3:67

“Or were you witnesses when death approached Jacob, when he said to his sons, “What will you worship after me?” They said, “We will worship your God and the God of your fathers, Abraham and Ishmael and Isaac – one God. And we are Muslims [in submission] to Him”.Quran 2:133

“Or do you say that Abraham and Ishmael and Isaac and Jacob and the Descendants were Jews or Christians? Say, “Are you more knowing or is Allah ?” And who is more unjust than one who conceals a testimony he has from Allah ? And Allah is not unaware of what you do.”Quran 2:140

Say, “We have believed in Allah and in what was revealed to us and what was revealed to Abraham, Ishmael, Isaac, Jacob, and the Descendants, and in what was given to Moses and Jesus and to the prophets from their Lord. We make no distinction between any of them, and we are Muslims [submitting] to Him.”Quran 3:84