The writer of the Book of Hebrews explains:
"Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high;" (Hebrews 1: 3)
"But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;" (Hebrews 10:12)
Today, men and women who believe in Jesus do not forgive out of a sense of obligation.
We forgive graciously, because Jesus has so freely forgiven us!
"31Let all bitterness, and wrath, and anger, and clamour, and evil speaking, be put away from you, with all malice: 32And be ye kind one to another, tenderhearted, forgiving one another, even as God for Christ's sake hath forgiven you." (Ephesians 4: 31-32)
In fact, the blood of Jesus is so powerful, that His blood, far better than of bulls and goats, cleanses (present tense!) forever!:
"But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin." (1 John 1: 7)
"1My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous: 2And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world." (1 John 2: 1-2)
There may be Christians who believe that they "have to forgive", but that does not diminish the blessed goodness of God our Father, and the blessed sonship which we receive from Him through Jesus.
In fact, there is nothing but goodness and glory for Christians, many of whom have yet to learn of the incredible inheritance offered to us:
"Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ" (Ephesians 1: 3)
" God, who is rich in mercy, for his great love wherewith he loved us, 5Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;) 6And hath raised us up together, and made us sit together in heavenly places in Christ Jesus: (Ephesians 2:4-6)
"31What shall we then say to these things? If God be for us, who can be against us? 32He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things? 33Who shall lay any thing to the charge of God's elect? It is God that justifieth. 34Who is he that condemneth? It is Christ that died, yea rather, that is risen again, who is even at the right hand of God, who also maketh intercession for us." (Romans 8: 31-34)
There is so much about the blood of Jesus, about the grace of God, which we simply do not understand (yet!). Forget the doctrines of men, but look at the Word of God.
This forgiveness did come to us after we believed on Him. God moved first to grant us grace:
6For when we were yet without strength, in due time Christ died for the ungodly. 7For scarcely for a righteous man will one die: yet peradventure for a good man some would even dare to die. 8But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us. 9Much more then, being now justified by his blood, we shall be saved from wrath through him." (Romans 5:6-9)
The grace of God does not depend on us. He has provided a payment for our sins. We can extend this grace to others, but whether they accept it is up to them.