Forgive is only mood making .none can really forgive

karma takes its course , cannot be undone"

"Man made law is inadequate natural law has no shortcuts"

"Laws of nature are infallible one reaps what one sows

a murderer cannot escape by praying , though with all sincerity

''universe reacts to individual action'', ----maharishi

Every action, good, bad, heinous, noble, base,--all have corresponding repercussions, inescapable by any means,

the course of action, the effects, the consequences vary from gross to subtle, extending long, wide, far in to time and space like the circles of waves / ripples when a stone is thrown on in water in a very large lake 

prayer/ forgiving etc at best gives some solace and strength to bear the inevitable consequences of bad karmas

othe sane advice is '' heyam dukham anagatham ''''avert the danger not arrived''

the technique is ''yogastha kuru karmani''ie ''be established in alignment with laws of nature perform actions'',

so that every action, even every impulse of doing the action comes out to be good and life supporting this is the skill in action by which man lives a life free from mistakes 

since consequences of mistakes cannot be escaped , it’s wise not to do mistake prevention is better