So what are you trying to conclude from this?
There is a big difference between the word "a" and the word "the" especially when the word "Holy" is added to it. The words "the Holy Spirit" identify a particular spirit. It is a proper name for a specific spirit.
Even Isaiah recognized that with the use of the word "the" in front of "Spirit". Not just any spirit, or a spirit, but "the Spirit of the Lord God", and Jesus then tells us more regarding his name with the addition of the word: "Holy". His name is "the Holy Spirit".
Who did Jesus send to his apostles when he ascended and sat down next to His Father?
Not a who but a what.
What? Holy spirit. Spirit that is holy. pneuma hagion
Holy spirit was sent. No definate article in the Greek. The definate article "the" was added in translation to substantiate faulty theology.
Don't believe me? just look at any interlinear or concordance.