Here "heaven" and "earth" refer to the entire universe. Alternate translation: "as long as the universe lasts" (See: [[rc://en/ta/man/translate/figs-merism]])
The jot was the smallest Hebrew letter, and the tittle was a small mark that was the difference between two Hebrew letters. Alternate translation: "not even the smallest written letter or the smallest part of a letter" (See: [[rc://en/ta/man/translate/figs-explicit]])
This can be stated in active form. Alternate translation: "all things have happened" or "God causes all things to happen" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The phrase "all things" refers to everything in the law. Alternate translation: "everything in the law" or "all that is written in the law" (See: [[rc://en/ta/man/translate/figs-explicit]])