Was not the Holy Ghost the one that informed all the messengers and prophets that was already with them?

I'm confused here.After jesus died YHVH's "Holy Spirit" came over or into the apostles,after the apostles died i can't find anywhee else that YHVH's "Holy Spirit" entered anyone else,it must have been alot easier for the prophets of the Old Testament and the apostles in the New Testament to believe,have faith,and preach the word than it is for humans today.