Why is it difficult for Muslims to believe that Jesus is the only Son of God, even though he is referred to as the Son of God in the Gospel and says of God: "My Father"?

The Gospel believed in by Muslims is the one that Jesus, peace be upon him, brought from Allah Almighty, and not the Gospel currently in the hands of Christians, which Muslims believe has been distorted and altered. Specifically, the Gospel of John is considered the most explicit in proclaiming the divinity of Christ, and many Christian researchers themselves have doubted its authorship and attribution to John the Apostle. Furthermore, it was written specifically to prove the divinity of Christ, which other Gospels had neglected.

The claim that Christ is the Son of God based on Gospel texts is a mistaken understanding. The same texts apply the description "Son of God" to Adam, Israel, and Solomon, a metaphorical sonship meaning a righteous servant, and it does not refer to a true sonship or a special status for Christ. The proof of this is that the Gospel itself mentions that believers in God are "sons of God," and Christ says that God is "My Father and your Father, and My God and your God." This confirms that the alleged sonship is a metaphorical sonship that includes all righteous people, is not exclusive to Christ, and does not imply his divinity.