Spirit of God?

^6-7 The Spirit of God came on Saul when he heard the report and he flew into a rage. He grabbed the yoke of oxen and butchered them on the spot. He sent the messengers throughout Israel distributing the bloody pieces with this message: “Anyone who refuses to join up with Saul and Samuel, let this be the fate of his oxen!”
^7-8 The terror of God seized the people, and they came out, one and all, not a laggard among them. Saul took command of the people at Bezek. There were 300,000 men from Israel, another 30,000 from Judah.

 The verse talks about the spirit of God. The biggest question is why is there? In the new testament, we know that Jesus came down from heaven to die for all our sins. And with His death. "He is in us". And by "He is in us", we receive the holy spirit. But in the old testament, it was exclusive, exclusive to people who had a very close relationship with God . The spirit of God caused them perform prophecy on those selected people. And in the beginning, Genesis:
And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.

Spirit of God was hovering across the waters. We see that it is an entity. And now we all have the entity, Holy Spirit in all of us. We should use it to the maximum! Communicating with God frequently. We have the privilege, so we should make the best out of it.