Excellent question! * What are the jot and tittle in Matthew 5:18 [KJV]?
In Hebrew, the "Yod" (י) is the smallest letter of the Alef-Beyt and used numerically in the Masoretic text to note #10.
In the Tanakh, "Yod" represents a #possessive hand used as a suffix with nouns like 'My-Help' ( עֶזְרִי ) from [Psalm 121:2]
The word 'Yod' (יד) is literally a #Hand of YHVH in [Ezekiel 37:1] "The Hand of YHVH" ( יַד יְהֹוָֽה ) came upon him.
In context to Matthew 5:18, Yeshua (Jesus) of Nazareth is making a deeper metaphor in stating God's Hand (Yod) will not pass away from the law. The Greek mistransliteration ' ἰῶτα ' (iota) loses the meaning.
'Tittle' (Stroke) refers to Latin (titulus) mistranslated from the Greek ' κεραία ' (keraia) from the Hebrew term 'Kera' ( כְרָעַ֨ ) - meaning the 'leg' a letter stands on. To Greeks, the 'Kera' meant a horn instead of leg, so scholars assume Yeshua meant the 'heel' stroke of a Dalet (ד). - Tittle is not referring to a 'dot' or 'dagesh', because the niqqud used by Masoretes was not applied to Hebrew manuscripts before 70AD. Which means Yeshua (Jesus) did not refer to niqqud.