Jesus was talking about the Holy Spirit. The Spirit had not yet been given, because Jesus had not yet been raised to glory. But later, those who believed in Jesus would receive the Spirit.
‘God says: In the last days I will pour out my Spirit on all kinds of people. Your sons and daughters will prophesy. Your young men will see visions, and your old men will dream dreams.
You should know that your body is a temple for the Holy Spirit who is in you. You have received the Holy Spirit from God. So you do not belong to yourselves,
Does God give you the Spirit and work miracles among you because you follow the law? No, he does these things because you heard the Good News and believed it.