Venerable Ru Jun’s discourse covers this topic. I share my own understanding (in English) with respect to relevant parts of the notes from the YouTube video.
(a general way to forgive someone is to see that the person himself is in suffering. Recognising that he is under torment, we will be able to forgive and also to see that we should help this person)
下，看到他那個樣子，我怎會跟他計較？(if a disabled person on a clutch happens to knock into us ,would you get angry at him seeing his state?)
有可以真正離苦得樂的希望，為什麼要因小而失大？(I have chanced upon a way for happiness with Buddhism. Why would I get petty over such small transgressions)
三、我只會被自己的惡業所傷，責任不在他，為什麼不能原諒？(I will only be harmed by my own karma. The fault does not lie with the other party. Why shouldn’t I forgive him then?)
四、“宿業所引發，令他損惱我，因此若墮獄，豈非我害他？”。(It is my karma and my responsibility that has led the other person committing bad karma)
Apologies if my understanding is incorrect.