Because in the old testament, many people had the Spirit of God to come upon them.
Joseph of old testament in
Genesis 41:38-39. Had the Spirit of God.
The book of Numbers 24:2.
The book of Judges 6:34.
The book of 1st Samuel 16:13, And the Spirit of the Lord came upon David.
So how is it you say, that the Spirit of God didn't come upon people in the old testament?
All throughout the old testament we can find the Spirit of God came upon many people.
Do you see Jesus in the OT? The Jews said that God was their father.
John:
43 Why do ye not understand my speech? even because ye cannot hear my word.
44 Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.
45 And because I tell you the truth, ye believe me not.
John:
17 For the law was given by Moses, but grace and truth came by Jesus Christ.
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.
Matthew:
And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart,
2 And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light.
3 And, behold, there appeared unto them Moses and Elias talking with him.
4 Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elias.
5 While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him.
6 And when the disciples heard it, they fell on their face, and were sore afraid.
7 And Jesus came and touched them, and said, Arise, and be not afraid.
8 And when they had lifted up their eyes, they saw no man, save Jesus only.
Mark out of context:
The beginning of the gospel of Jesus Christ, the Son of God;
And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and
believe the gospel.
And
the gospel must first be published among all nations.
And he said unto them,
Go ye into all the world, and preach the gospel to every creature.
It is clear to me to teach Christ. For neither Christ nor Gospel appears in the OT. Jesus said that the Jews died without it.
John:
This is that bread which came down from heaven:
not as your fathers did eat manna, and are dead:
he that eateth of this bread shall live for ever.
Only the Gospel that Christ taught can save man.