The reason you are wondering this is because you have a misconception.
You are confusing and conflating two things. You think having the holy spirit is synonymous with being regenerated. While both things are true of New Testament believers, they is still two distinct things.
The proof that are you conflating the two things is because in your opening post, you said:
And then in post #5, you said:
So, this proves that you think having the Holy Spirit and regeneration are one and the same thing.
Regeneration and having the holy Spirit are related, but two different things.
A man obeys because he has been regenerated.
The indwelling of the Holy Spirit is unique to New Testament believers. It is a gift from God, it is something that makes the new covenant different than the old covenant.
Jesus told his disciples that he would give them a gift, the indwelling holy spirit. Prior to the New Covenant, people were regenerated, but they didn't have the indwelling Spirit in the same way New Testament believers do. In the Old Testament, the Spirit would come and go from the saints, empowering them for service but not necessarily remaining with them. In the New Testament, Jesus revealed to His disciples the new role the Spirit of Truth would play in their lives: “He lives with you and will be in you” (
John 14:17).
So, to answer your question, the way a person obeys is because of regeneration. That is how people have always obeyed, even in the Old Testament before the Indwelling Spirit was given to believers as a gift. A person then is sealed with the holy spirit because of their faith.
To reiterate, having the indwelling Spirit and being regenerate are not the same thing, though they are both true of Christians in our new covenant.