The reason why the Jews, headed by the Pharisees, priests and scribes, did not accept that he was the Son of God, is because they believed that only God could save and, considering himself their Son, would make him their equal; the truth is that the only way for God to have someone identical to Him, would be to make Himself man or son of man; by incarnating Himself in a mortal body.

God declared Himself the Savior of lost humanity, and Jesus was announced as the spotless Lamb who takes away the sin of the world, the Redeemer or Physician of the lost.

Isaiah 45:22 NKJV

22 “Look to Me, and be saved, all you ends of the earth! For I am God, and there is no other.

Isaiah 44:6 NKJV

6 “Thus says the Lord, the King of Israel, and his Redeemer, the Lord of hosts: ‘I am the First and I am the Last; Besides Me there is no God.

Isaiah 42:8 NKJV

8 I am the Lord, that is My name; And My glory I will not give to another, nor My praise to carved images.

John 5:23-24 NKJV

23 that all should honor the Son just as they honor the Father. He who does not honor the Son does not honor the Father who sent Him.
24 “Most assuredly, I say to you, he who hears My word and believes in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death into life.

Acts 4:11-12 NKJV

11 This is the ‘stone which was rejected by you builders, which has become the chief cornerstone.’ 12 Nor is there salvation in any other, for there is no other name under heaven given among men by which we must be saved.”