The word revelation means: ’an uncovering, or a laying bare or to unveil. Or, a disclosure of truth, instruction of divine things that were before unknown given to the soul by God himself, or by the ascended Christ, especially through the operation of the Holy Spirit.’ (From Strong’s and Vine’s Dictionaries)
In my own experience it was very much as described above. Things were unveiled that I didn’t know before about Jesus. I knew about religion, I knew church, I knew the ‘one-two-three and you’re in’ salvation message, and I knew the ‘just raise your hand or come down to the front’ and ‘you just need to get baptized.’ In my early twenties I began dabbling to learn about the Holy Spirit. I was about 25 years old before anyone told and led me to being baptized in the Holy Spirit. It was a revelation of Jesus Christ the Son of God. It is more real today than it was then.
Paul, an apostle, wrote to the Corinthians:
“But it was to us that God revealed these things by his Spirit. For his Spirit searches out everything and shows us God’s deep secrets. No one can know a person’s thoughts except that person’s own spirit, and no one can know God’s thoughts except God’s own Spirit. And we have received God’s Spirit (not the world’s spirit), so we can know the wonderful things God has freely given us.” (1 Corinthians 2:10-12 NLT)
“And I will ask the Father, and he will give you another Advocate, who will never leave you. He is the Holy Spirit, who leads into all truth. The world cannot receive him, because it isn’t looking for him and doesn’t recognize him. But you know him, because he lives with you now and later will be in you.” Jesus