Quar'an Jesus

In early versions of his stage persona, William Branham taught the Christian viewpoint that Jesus Christ was the Son of God as described in the third chapter of John in the New Testament. . In Christianity, it is believed that Jesus Christ was God's only begotten son, born of the virgin Mary.

For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life.
John 3:16

Early versions of William Branham's stage persona affirmed this belief and considered any who disagreed with John 3:16 to be an "infidel". In the Islamic version of Jesus, it is believed that Jesus Christ was not the "Son of God", but instead the "Son of Man".

Many infidels tell you, "Jesus never did claim to be the Son of God." He did there; yeah. He said, "I am He that speaks with you." Branham, William. 1960, July 16. From That Time.

In this context, "Son of Man" refers to a mortal prophet. Muslims believe that Jesus was a prophet of Allah. This would have been offensive to the Islamic community; William Branham used the offensive slur, "infidels" against the Islamic faith.

God says: "Lo! the likeness of Jesus with Allah is as the likeness of Adam. He created him from dust, then he said unto him: Be! and he is." (3:59) It is important to realize that Jesus, on whom be peace, never taught that he is the Son of God. God says in the Quran that those who call Jesus "Son of God" are following the saying of other people (see 9:30). Jesus taught only what he was commanded (5:117). He himself was quite pleased with being a servant of God (4:172). As a messenger of God, Jesus knew that none in the heavens or the earth can approach God except as a slave (19:93).
Why Islam. The Messiah: Jesus, Son of Mary

When Branham transitioned into the later version of his stage persona, however, he began to promote himself as the return of "Elijah" the prophet from the Old Testament. In this version of his stage persona, he alleged to be God Made Flesh, Not a man but god.

But the Elijah of this day is the Lord Jesus Christ. He is to come according to Matthew the seventeen-…Luke 17:30, is, the Son of man is to reveal Himself among His people. Not a man, God! But it'll come through a prophet.
Branham, 1965, Nov 27. Trying To Do God A Service Without It Being God's Will

After making this transition, Branham's stage persona sided with Islam in their doctrinal teaching against the Christian doctrine that Jesus Christ was the Son of God

Now, He had to come as Son of man, because He was a Prophet. Jehovah, Himself, called the prophets, "son of man." And Jesus never referred to Himself as Son of God. He referred to Himself, always, as Son of man. And notice, He revealed Himself then as the Prophet, the Seer. Said, "If I do not the works of My Father, then believe it not." He met every description that was spoke of Him in the Scripture, even to His death, burial, resurrection; His crucifixion, His birth, all. And in His work, He met the description of the Seer, the Son of man.
Branham, 1964, July 19. The Feast Of The Trumpets