“Fulfill” doesn’t imply ended

Answer:

The word "fulfill" in Matthew 5:17 originates from the Greek word pleroo, which means "to fill, make full, supply fully, or complete." Its meaning can be seen in how it is used in other passages. For example, numerous passages refer to actions taken so that a prophecy might be fulfilled, such as in Matthew 1:22, 2:15, and 17, among others. The word means that the prophecy was answered in full and brought to completion. When a task is completed to the fullest extent, it is finished. We say this in English when we say we went to the gas station and filled up the car. In other words, we stopped pumping gas into the car once it reached the full mark because no more gas could be added. This sense of a completed purpose is seen in Luke 7:1, "Now when He concluded all His sayings in the hearing of the people, He entered Capernaum." The word "concluded" is the Greek word pleroo. Jesus fulfilled his purpose in that particular lesson. Nothing more needed to be said at that moment, so he stopped. It is also seen in Acts 19:21, "When these things were accomplished, Paul purposed in the Spirit, when he had passed through Macedonia and Achaia, to go to Jerusalem, saying, 'After I have been there, I must also see Rome.'" Paul had completed what he set out to do in Ephesus, so he looked to move on to another region. The same Greek word pleroo is being used, though it is translated as "accomplished."

By stating that the law would continue until all was fulfilled or made complete, Jesus implies that the law in its current state was not complete. We know from the apostles’ writings that the Mosaic Law was missing some essential parts. It could not give its followers life (Galatians 3:21) or make them perfect (Hebrews 7:18-19). Thus, it had a fault, not in itself, but in the inadequacy of those who tried to live by it (Hebrews 8:7). It could explain and hold a person accountable for sin, but in itself, it could not cleanse sin (Hebrews 10:1-4, 8-10, 14). It was Jesus' sacrifice that brought the missing elements into existence (Hebrews 9:15).

The difference between destroying and fulfilling the law is the same difference between declaring a mortgage note null and void, tearing it up and throwing it into the fire, and paying the note off in full. Both bring the mortgage to an end, but they do so in vastly different ways. Jesus did not cancel the law but brought it to a natural conclusion.

Jesus explained what he meant by "fulfilled" when he emphasized that the Law would not end until all was fulfilled. “For assuredly, I say to you, till heaven and earth pass away, one jot or one tittle will by no means pass from the law till all is fulfilled” (Matthew 5:18). This "fulfilled" comes from a different Greek word, ginotai. It means "to be, to come into being, to be made, be done, become, or to be celebrated." Jesus stated that the permanence of the law was conditional. He gave two possible ending conditions: either heaven and earth would come to an end, or all would be accomplished. His phrasing is similar to that of a parent who tells his child, “You’ll sit here all night until you eat your peas.” The implication is that the child would not be at the table all night; the peas would be eaten before then. In the same way, Jesus is saying that the world would have a better chance of ending than God failing to accomplish His purpose for the Law. Some people focus so hard on the first condition that they overlook the fact that the second condition would occur before the first. A similar phrasing can be found in Matthew 24:34 and Luke 21:31-33.

Another verse that speaks to this same topic is Romans 10:4, "For Christ is the end of the law for righteousness to everyone who believes." The word translated as "end" is from the Greek word telos, which means "end, termination, conclusion, aim, result, goal, outcome." In other words, the purpose of the Law culminated in Christ Jesus. Jesus was its goal. With his death, he brought the law to its conclusion. "Having wiped out the handwriting of requirements that was against us, which was contrary to us. And He has taken it out of the way, having nailed it to the cross" (Colossians 2:14). Or as we already noted, "Therefore the law was our tutor to bring us to Christ, that we might be justified by faith. But after faith has come, we are no longer under a tutor" (Galatians 3:24-25).

In Matthew 3:15, Jesus told John that his baptism should take place to fulfill all righteousness, not to fulfill baptism as you claimed. To fulfill the Law, Jesus needed to keep all that was commanded, including the recent addition of baptism by John, the last prophet under the Old Law. Jesus brought his requirement to be righteous to the full.

In Romans 15:19, Paul said he completed his task of teaching the Gospel in the regions from Jerusalem to Illyricum. He had no additional things that needed to be taught in that region, so he is planning to travel to Spain to cover new territory with the same message (Romans 15:22-24).

You seem to think that any reference to "command" refers to the Ten Commandments, which is provably false. See "Does the word 'commandments' always refer to the Ten Commandments?"