If we look at things at face value,we could easy make a case of saying Muslims.Jews,and Christians worship the same God,in that we worship the God of Abraham.But if we consider the whole picture as is revealed in Gods word we see a different picture, Islam exalts Ishmael above Isaac which
is not what the Bible teaches,because it would be through Isaac Gods redemptive purposes would be fulfilled.Likewise when it comes to the
Jews, they reject the promise Saviour,for Jesus is that promised seed though
whom all the earth would be blessed[Genesis 22v18].If we say that Muslin's,Jews and Christians worship the same God,saying that is not taking into consideration the full story,as revealed in scripture.Jesus is that promised Seed of Abraham,if Muslims, and Jews reject that seed,then the god they worship,is not the same as the God the Christians worship and the Jew have chosen another way, than that, which is revealed in Gods word.
Islam ,Judaism both have a limited an imperfect concept of Abraham,who rejoiced to see Christs day,and saw it and was glad[John 8 v56].As D.A.Carson writes,/Jesus identified the ultimate fulfilment of all Abraham's hopes and joys with His own person and work/.
Dear God we thank you for Jesus the promised seed of Abraham,through whom all the earth is blessed, He is the only one,who can forgave our sins,and make us true children of Abraham,and true Children of God.Amen.