The stroke that keeps two letters apart
“Till heaven and earth pass away, one jot or one tittle shall in no wise pass away from the law.” The jot is iota — Greek for yod, the smallest letter in the Hebrew square script. The tittle is keraia, “little horn”: the tiny stroke that keeps two near-identical letters from becoming each other.
Resh is one half of the most famous of those pairs. ד dalet and ר resh differ by one small corner. So do ב and כ. So do ה and ח. Copying Hebrew faithfully means keeping strokes that small, and a scribe who lets one slide changes a word.
Notice what Jesus's argument is and is not. It is not about hidden meanings inside letters. It is about preservation — the text is kept down to the stroke. Yod's room carries this one in full.