So, it isnt necessary to believe in Jesus as a Savior to be saved. It is sufficient to believe in God, and do good. (faith and work)
For those who believe that salvation comes only through believing in Jesus as a Savior. Then, why didnt God send Jesus as the first prophet so that all the coming prophets and believers got salvation?! Do you think that God changed "His mind": He sent the prophets with the message of worshiping God only. While, He sent Jesus with the massage of worshiping God, Jesus, and Holy Spirit?!! Why is this change?!!
No not quite.. having faith is basically believing without seeing or without proof. Maybe even believing when the proof says otherwise..
They believed in the coming Messiah the promised one.. the redeemer.. You are trying to fit Christianity and the Bible into your Islamic box. I understand that you are looking for some way that we got it wrong to prove Islam right. Im sorry friend it will not work. Jesus was alive and well in the Old Testament.. He was just not called Jesus yet. He was there in the beginning as the Word. He walked with Adam and Eve. He wrestled with Jacob. He spoke with Moses. He spoke and ate with Abraham and Sarah. He was there as GOD YHWH Elohim El Shaddai .... all of the above... as well as the Lord and the Angel of the Lord (angel means messanger btw) and He became Man and was also God so that the world could be saved through Him.
God Bless you on your journey Dialogue.