Question: If one has not taken the precepts, and had broken all of them, what happens if one commits to take them later?
Answer: There will be more regular good (positive) karma generated throughout life as it is a resolution to not harm others for life.
Question: Will past bad karma still catch up with one for the past wrongs done?
Answer: This might or might not happen. It depends on whether there is sufficient good karma generated in time to effectively dilute the effects of past bad karma. Just do your best! Please don’t hesitate to take the precepts. It is always better late than never, and always does more good than evil.
Question: How can one ensure not breaking the precepts again if one still breaks them after taking them?
Answer: One can go through the precept-taking ceremony again if there was serious breaking of precepts, or repent before a Buddha image or Buddhist teacher. The idea is to be as sincere as one can in expressing realisation of a mistake, and to sincerely resolve not to repeat it.
Question: If someone broke the precepts to harm us, but asked for our forgiveness, would forgiving them the same as breaking the precepts ourselves?
Answer: It is breaking of precepts on the wrong-doer’s part, while it does not break any precept on our side to forgive. The apologising which creates some good karma, will help to mitigate the effects of the bad karma created. It is good to forgive. But it would be unskilful if one’s expressed forgiveness feeds the wrong-doer’s continual breaking of precepts. One might need to be skilfully stern and firm while accepting the apology, so as to express expectation of the wrong-doer’s commitment to not repeat the mistake.
Related Article:
Is It Better Not To Observe Any Precepts?
https://thedailyenlightenment.com/2010/02/is-it-better-not-to-observe-any-precepts