Jesus said, "Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.
For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven." (Matt.5:17-19)

l.  Jot  (The smallest letter)

    A.  Strong's Con. NT#.2503 / ἰῶτα iōta, ee-o'-tah; of Hebrew origin (the tenth letter of the Hebrew alphabet);   
         "iota", the name of the eighth letter of the Greek alphabet, put (figuratively) for a very small part of
         anything:—jot.
    B.  Thayer's Greek Lexicon / STRONGS NT 2503: ἰῶταἰῶτα, τό, iota (A. V. jot), the Hebrew letter, yodh י, the
         smallest of them all; hence equivalent to the minutest part: Matthew 5:18. (Cf. Iota.)
                   THAYER’S GREEK LEXICON, Electronic Database. Copyright © 2002, 2003, 2006, 2011 by Biblesoft, Inc.All rights reserved. Used by permission. BibleSoft.com

ll. Tittle  (not even the minutest part of the law shall perish.)

    A.  Strong's Con. NT#. 2762 / κεραία keraía, ker-ah'-yah; feminine of a presumed derivative of the base of
         G2768; something horn-like, i.e. (specially) the apex of a Hebrew letter (figuratively, the least particle):—tittle.
    B.  Thayer's Greek Lexicon / STRONGS NT 2762: κεραίακεραία (WH κέρεα (see their Appendix, p. 151)), κεραιας, ἡ
         (κέρας), a little horn; extremity, apex, point; used by the Greek grammarians of the accents and diacritical
         points. In Matthew 5:18 ((where see Wetstein; cf. also Edersheim, Jesus the Messiah, 1:537f)); Luke 16:17 of t
         he little lines, or projections, by which the Hebrew letters in other respects similar differ from each other, as
         cheth ח and he ה, daleth ד and resh ר, beth ב and kaph כ (A. V. tittle); the meaning is, 'not even the minutest
         part of the law shall perish.' ((Aeschylus, Thucydides, others.))
                 THAYER’S GREEK LEXICON, Electronic Database. Copyright © 2002, 2003, 2006, 2011 by Biblesoft, Inc.All rights reserved. Used by permission. BibleSoft.com  

lll.    Whosoever therefore shall break the fulfillment one of these least (even to the jot and tittle)and shall
         teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall (be in Christ
         2Cor.5:17, Rom.8:1-4) and do (Acts.1:1) teach them, the same shall be called great in the kingdom of heaven."
         (Matt.5:17-19)

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