Hi arunangelo,
Those who accept his forgiving spirit accept his forgiveness. On the other hand those who reject his forgiving spirit by refusing to forgive reject his forgiveness.
Personally, I believe there is a confusion of terms on the topic of the Atonement, the reconciliation which it brought between God and man at a spiritual level, and the need for a response by each individual person in order to receive his/her own 'remission of sins' through faith in the power of Christ's blood.
When John the Baptist was preaching and prophesying, he was calling people to make a response. Unless they came forward for baptism, they could not experience the remission of their sins. In the same way, those of mankind who do not approach the Father through Christ Jesus, cannot experience the forgiveness of their sins, even though Christ's death and resurrection, the barrier to fellowship with God has been removed.
It is vital that each person complies with the terms of God's invitation, in order to receive the benefits of His provision for us in Christ.
Following on from this, when a person has experienced how totally their past sins are forgiven, they are finally equipped to forgive others. Although one can use certain verses in the gospels to make it sound as if a person cannot become a Christian until they have forgiven those who have sinned against them, there is no logical or practical reason for making that stipulation. When Jesus was speaking, He was talking about something that hadn't really happened in their experience, yet. We can see this if we look for the references to 'conscience' in the apostles' writings. There is no doubt that before the New Covenant, even those who kept the Mosaic law perfectly, could not testify to a
clear conscience.
My experience of being forgiven, is partly about forgiving myself too, but until I had tasted the superior qualities of the forgiveness of God within my own soul, I had no strength to forgive others.