This cleansing is needed for our sanctification, peace of mind, and communion with God. We don't need to be saved over and over again. But, we need to be cleansed on a daily basis, as we still err and are imperfect. First the cleansing of the whole body, then our feet washed by Him, and also the washing of each others feet. My little children, these things write I unto you, that ye sin not.
Forgiveness is for the asking.
We must repent of our sins and come to Him with a contrite spirit. Nowhere in the Bible do we read that Jesus questioned those who came to Him for forgiveness. He did not even ask the woman at the well about her five husbands. I can just see the eyes of Jesus looking straight at the woman, full of compassion, no condemnation. As God in Christ forgave you, so you must forgive also.