Commentaries:
Robertson's Word Pictures (NT)
One jot or one tittle (iwta en h mia kerea). "Not an iota, not a comma" (Moffatt), "not the smallest letter, not a particle" (Weymouth). The iota is the smallest Greek vowel, which Matthew here uses to represent the Hebrew yod (jot), the smallest Hebrew letter. "Tittle" is from the Latin titulus which came to mean the stroke above an abbreviated word, then any small mark. It is not certain here whether kerea means a little horn, the mere point which distinguishes some Hebrew letters from others or the "hook" letter Vav. Sometimes yod and vav were hardly distinguishable. "In Vay. R. 19 the guilt of altering one of them is pronounced so great that if it were done the world would be destroyed" (McNeile).
Other Robertson's Word Pictures (NT) entries containing Matthew 5:18:
Luke 16:17
James 2:10
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