If this is a conversation you will need some punctuation. I am the sheriff here. Nobody is going to question my orders! Now listen Jack, what you've done is unforgivable. If it weren't for me laying down the law every time, you would be in jail by now.

I think that some super strict teachers would require a comma before and after "Jack": Now listen, Jack, what you've done is unforgivable. Compare: Jack, now listen, what you've done is unforgivable. Now listen, what you've done is unforgivable, Jack.

The last sentence needs some attention. It should be either: "If it weren't for me laying down the law every time, you would be in jail by now." or "Were it not for me laying down the law every time, you would be in jail by now." ("Weren't it" is the wrong word-order.)

thank you everyone for answering my question.