Mark 1:1
Mark 1:11This is the beginning of the gospel of Jesus Christ, the Son of God.
"Son of God" is read as a title of relationship and rank rather than of nature — Jesus is God's Son in the way the angels are called sons of God in , or as Adam is called God's son in Luke's genealogy. The Watchtower is comfortable with this verse because it distinguishes Jesus from God rather than identifying him with God, and JWs will often cite the phrase as evidence that the Gospel writers knew Jesus was someone other than the Almighty.
Nobody disputes that "Son" implies distinction — Trinitarians affirm it. The question is what kind of son. Mark answers it in the next two verses rather than in this one, so don't stop at verse 1. Mark opens his Gospel by stitching together and , and both prophecies are about Jehovah coming in person. Malachi has Jehovah say "I am sending my messenger, who will prepare the way before me" — before me, in the first person. says to prepare the way of Jehovah. Mark quotes both and then puts John the Baptist in the messenger's role and Jesus in the role of the one being prepared for. That is the claim Mark makes in his first three sentences, and he makes it by citation rather than by assertion. So the doorstep move is simply to keep reading. Ask who verse 3 says the road is being made ready for, then ask who actually walked down it. Compare , .