I believe the Holy Spirit Of God always has been and always will be in the hearts of all who believe since the beginning of creation. So what is Pentacost, and why do they say the Holy Spirit wasn’t given until after Jesus when the bible testifies otherwise?

Exodus 35:31 “and He has filled him with the Spirit of God, in wisdom and understanding, in knowledge and all manner of workmanship”
Exodus 36:1 “And Bezaleel and Aholiab, and every gifted artisan in whom the Lord has put wisdom and understanding, to know how to do all manner of work for the service of the sanctuary, shall do according to all that the Lord has commanded.”

Mark 6:7 And He called the twelve to Him, and began to send them out two by two, and gave them power over unclean spirits.
Luke 10:1 After these things the Lord appointed seventy others also, and sent them two by two before His face into every city and place where He Himself was about to go. Luke 10:9 "And heal the sick who are there, and say to them, “The kingdom of God has come near to you.”

I don’t know. I have always been confused over “If I do not go, the helper will not come” or, rather “It is for your benefit that I go”. This is from memory, but I was always confused by this. If the Holy Spirit was present before, then why did Christ have to go in order for the Holy Spirit to come? This scripture has always perplexed me and I have not encountered a commentary that has shed any light on this one.