It's tempting to make this a tutorial but I'd rather it be a testimonial, so I'll endeavor to keep it that way.
Not very long after my conversion back in 1968, I ran across a passage in the New Testament that caused me some anxiety. It goes like this:
"You are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his." (Rom 8:9)
It seemed reasonable to me that if the Spirit of Christ was actually inside my body, I should be able to detect His presence. I mean, how could somebody like that possibly be in there without my knowing it?
When I shared my concern with a pastor whom I had come to trust, he reminded me that the Spirit of Christ is a paranormal being consisting of something less than thin air, and that as such can move about imperceptible to the five natural senses, viz: hearing, sight, taste, touch, and/or smell.
So, he steered me away from empirical evidence and instead turned my attention towards scriptural evidence. He said-- in so many words --if it's true that Christ's sheep have his spirit, and you can prove yourself to be Christ's sheep, then you've proven yourself to have his spirit.
( Euclid couldn't have said it better )