Firstly, God so loved the world that He gave his only begotten Son; this is what love is all about. We know that Jesus Christ died for us and He does offer salvation to all. In knowing this truth, we must accept that it is possible for anyone to repent, although we may never see it. Therefore, we simply must accept that it is "for" God and "given" to God. We must then be accepting that some things are beyond us to understand or know. We give judgment up to God. If you break down the word further, it is "for" God to know and "given" to God to be the righteous judge.
However, we must also be aware that God Almighty has made it clear in his word there are two types of punishments for sin - either total destruction (death and eternal damnation to the most horrible of all places, which is hell) - OR repentance (and the punishment goes to Jesus Christ). Repentance must involve a salvation exchange with Jesus Christ, for sin is only forgiven by His Blood on the cross. This standard (these choices) have been established by Almighty God, so obviously, it's what the Lord expects his servant to take into account when "forgiving" someone.
To be relieved of the sin of hate and condemnation, we are therefore called to pray (like David) to destroy our enemies, meaning, ask God to destroy evil and wicked deeds (and we know who the true enemy is):
"Destroy thou them, O God; let them fall by their own counsels; cast them out in the multitude of their transgressions; for they have rebelled against thee." (Psalm 5:10 kjv).
"Cast forth lightning, and scatter them: shoot out thine arrows, and destroy them." (Psalm 144:6 kjv)
"And of thy mercy cut off mine enemies, and destroy all them that afflict my soul: for I am thy servant." (Psalm 143:12 kjv)
"But the transgressors shall be destroyed together: the end of the wicked shall be cut off." (Psalm 37:38 kjv)
We must then for-give the person, asking that they somehow, some way, be led into salvation through Jesus Christ, Our Lord. In other words, to "for-give" means to give them to Jesus Christ, who is the only one worthy to sit upon the final judgment seat. And that's loving in the way that he commanded, instead of hating them for what they have done.
Either way, salvation or damnation, it's up to God and each individual (through their own choices), to determine what the punishment will be. It's not up to us to determine for anyone else. So the situation and the individual involved is "for" "given" to God for his perfect and righteous judgment. We must also ask Jesus to cover our own sins at all times, for it is only through Him that any of us are saved.