In Hebraic thought, to "fulfill" (l'kayyem, from qum, "to stand") means to uphold, validate, and correctly live out God’s Torah—His fatherly instruction—not to retire or discard it. You do not outgrow a father’s guidance; you fulfill it by keeping it standing through faithful obedience.

This permanence is guarded by the ultimate biblical warning against altering God's Word:

"And if anyone takes words away from this scroll of prophecy, God will take away from that person any share in the tree of life and in the Holy City..."

— Revelation 22:19 (cf. Deuteronomy 4:2, 12:32)

To fulfill the instruction is to preserve it intact; to alter or abandon it is to forfeit one's place in the life God promises.

Strictly by the rules of English grammar, Matthew 5:17 cannot mean the law is ended or retired.

The verse uses a classic not X, but Y contrast:

"I did not come to abolish... but to fulfill."

In plain English syntax:

Antonyms are required: "Fulfill" must mean the opposite of "abolish." If "fulfill" means to terminate, complete-and-dismiss, or set aside, the sentence becomes an absurd contradiction: "I did not come to do away with the law, but to do away with the law."

The context confirms it: Verses 18–19 immediately reinforce this by stating that not a single pen stroke will disappear until heaven and earth pass away, praising those who "practice and teach" the commands and warning anyone who "sets them aside."

Grammatically, treating "fulfill" as an expiration date directly contradicts the opening clause of the sentence.