There is a dimension of reality to our hope that cannot be explained away in terms of the psychological benefits of not feeling guilty. Forgiveness is powerful, but it is also real.
There is more to having hope than just knowing that we have been forgiven. It’s a good starting point, but without the Holy Spirit, we would be powerless to prevent ourselves from falling back into old ways, bad habits and self destructive desires.
The constant presence of the Holy Spirit to transform us was promised unequivocally by Jesus in John ch.16 v.7 onwards. His manifestation in our lives is not conditional on anything we could say or do. He is there because He is able to change us fro the inside out. He is there as a guarantee that what has been promised to us will come to pass.
That is why He guides us and empowers our prayers. He confirms to us that if God can do this through us on earth, then it is possible for Him to perform all that He has promised in our futures too. This is what motivated Paul when he wrote Ephesians ch.1 v.14.