Judaism, Christianity, and Islam.
Abraham!
The patriarch of the monotheistic religions of Judaism, Christianity, Islam, and the Baha'i Faith is/was Abraham.
Abraham
As far as we know Abraham did not have siblings that we know of.
Abraham was the christians father in faith and a person honored by the Muslims
Judaism regards Abraham as the first historic individual whose practices became foundations of Judaism. Christianity and Islam both acknowledge Abraham as a monumental figure in the evolution of their respective faiths, but certainly not as its 'father'. Our guess is that Christianity would accord that honor to Jesus, and Islam to the prophet Muhammad.
Abraham is considered the father of three major monotheistic religions: Judaism, Christianity, and Islam. His mission was to spread the message of belief in one God and to establish a covenant with Him. Abraham's willingness to sacrifice his son as a test of faith is also a significant aspect of his story.
Technicly he did not start the three religions because before him there was worshipers of God but, they died out so god called Abraham to revie his worship not what most scentist and historians baleive.
because he believed in god and did what he asked
Abraham is considered the father of Christians because he is a foundational figure in the Judeo-Christian tradition, recognized for his faith and covenant with God. In Christianity, he is viewed as a model of faith and righteousness, and his belief in God's promises is seen as a precursor to the faith that Christians are called to embody. Additionally, the New Testament often references Abraham to illustrate themes of faith and justification, establishing a spiritual lineage that connects Christians to the patriarch.
Isaac, the son of Abraham and Sarah, is a key figure in the Abrahamic religions. He is known for being the child of promise, born when Abraham was 100 years old, following God's covenant with Abraham. Isaac's life is marked by significant events, including his near-sacrifice by Abraham, which is seen as a test of faith. He married Rebekah and became the father of Esau and Jacob, continuing the lineage of the Israelites.
he is founder of 3 main monotheistic religions Judaism, Christianity and Islam.prophet Moses, Jesus (his mother Maria) and Muhammad all are children of Abraham. (peace on them all)Additional Answer:Because he fully believed and had complete faith in God the Word who tested him. He even complied fully to offering his son Isaac as God instructed him to. This faithfulness pictures God the Father's offering His Son for all mankind and made Abraham known as the father of the faithful.Romans 4:16New King James Version (NKJV) 16 Therefore it is of faith that it might beaccording to grace, so that the promise might be sure to all the seed, not only to those who are of the law, but also to those who are of the faith of Abraham, who is the father of us all