He that believeth on him is not judged: he that believeth not hath been judged already,
because he hath not believed on the name of the only begotten Son of God. τοῦ μονογενοῦς υἱοῦ τοῦ θεοῦ John 3:18.
How do you know if the Messiah is the Son of God?
Study the Bible,
the covenant made with Abraham was to inherit the Land of Promise, that is carried on throughout all of the scripture.
That same covenant is carried over in the belief that Christ is the Messiah,
the heir of that covenant.
That fact is explained by Mark:
"But those husbandmen said to themselves,
This is the heir; come, we may dehumanize him,
and the inheritance shall be ours". Mr 12:7
The whole Bible is based upon that Covenant, and until you can grasp that by asking God to "seek and find" you life will be in danger.
Heb 1:1 is explained by Heb 1:2 Where Christ is appointed the heir to the name "Son" of God. He is an heir because he is of the same linage as Abraham and obeyed God by submitting to DEATH, and was found a sacrifice thru that spotless offering to God as symbolized by the same way Abraham offered up Isaac.
While he was here among the disciples, he was a man, endowed with the POWER of the Holy Spirit.
After he was resurrected he is to become the High Priest and ruler of God's Kingdom, here on earth.
What is proven that he is more than just a common person, lies in the fact that he is NOW
"Sitting at the right hand of God until God makes his enemies a footstool for his feet".
The footstool is symbolic of the "Kingdom" of God.
That is why Luke used the future tense and said,
he shall be great,
and shall be called the Son of the Highest: and the Lord God shall give unto him
the throne of his father David:
And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end. Luk 1:32-33
In the Epistle to the Hebrews, it is said that when Abraham was ready to sacrifice Isaac he was offering up τον μονογενή, "his only-begotten" (11:17), because although Abraham had another son, God had said that only in Isaac shall Abraham's seed (σπερμα

be named.
You can also study the meaning of these scriptures:
Heb 1:13 And to which of the angels has he ever said,
"Sit at my right hand until I make your enemies a footstool for your feet"?
Heb 2:16 For verily he took not on him the nature of angels;
but he took on him the seed of Abraham.
Heb 2:17 Wherefore in all things it behoved him
to be made like unto his brethren, that he might be a merciful and faithful
high priest in things pertaining to God, to make reconciliation for the sins of the people.
John 1:18. No man hath seen God at any time;
the only begotten Son, which is in the bosom of the Father,
he hath declared him. ὁ μονογενὴς υἱός,
1 John 4:9. Herein was the love of God manifested in us, that God hath sent his only begotten Son into the world, that we might live through him.
τὸν υἱὸν αὐτοῦ τὸν μονογενῆ