Of course, we must forgive. When giving instruction on how to pray, Jesus included in Matthew 6:12, "And forgive us our debts, as we also have forgiven our debtors," (ESV). He added in Matthew 6:14-15, "For if you forgive others their trespasses, your heavenly Father will also forgive you, but if you do not forgive others their trespasses, neither will your Father forgive your trespasses," (ESV). So, if we want forgiveness, we must forgive.
It is impossible to forget unless one develops an illness, degenerative disease, or brain injury that causes memory loss. I understand why it's important to move on and not dwell on the past for negative purposes, but there is no way to erase the memory of the past.
God doesn't forget. He chooses not to bring our past mistakes up to use them against us. He forgives, but He doesn't forget. Psalm 103:12 says, "As far as the east is from the west, so far does he remove our transgressions from us," (ESV). He removes our transgressions from us, but He doesn't forget them. He forgives them. There is a difference.
In fact, in order to forgive we have to be able to remember. Otherwise, how will we know what we need to forgive if we don't remember what needs to be forgiven. God's remembrance is one reason why His forgiveness is so impacting. Though He remembers our transgressions, He forgives them anyway. Forgiveness is about remembering but doing right with what we remember.
In Joshua chapter 4, God told Joshua to have the people take twelve stones from the Jordan and build a memorial. The memorial was to be a sign to prompt their children to ask what the stones meant to them. They were to tell their children about their deliverence from Egypt, His provision in the wilderness and their crossing over the Jordan. He wanted them to remember and retell all of it. This story indicates to me that not only did God want them to remember, but He wanted them to remember on purpose. He wanted them to remember the past, not to throw it in their faces, but to remind them of His goodness towards them.
I refuse to allow my past to condemn me or others, but I don't want to forget. I want to remember. I want to remain very aware of where God brought me from. I want to continuously acknowledge what my life could be but isn't because of God's sufficient grace to me. And I want to be intentional about remembering. I want to build a memorial to who He is and what He has done for me.
When people see me, though they'll have to look hard, they'll probably see my scars—my memory stones. I want to be able to tell them what my memory stones mean if they choose to listen. Rather than regret and forget the past, I choose to recall and make meaning out of it—to build a memorial. Jesus changed my life. I think He wants me to remember. I think He wants me to tell others all about it.