Jesus Himself said the Old Covenant, the Agreement, was fulfilled. When a contract is fulfilled, it is basically void. In this case it was superseded by a new contract.
Matthew 5:18 "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."
Better check your hole card, you may have mistaken a deuce for an ace.
Matthew 4:17 points to the real path to salvation when Jesus said "repent for the kingdom of heaven is at hand". John the Baptist said the exact same thing. And Jesus himself said John was "the greatest of them all".
Unfortunately, you cannot completely understand what Jesus meant in this passage by this passage alone. Even the disciples took some time to grasp it. Peter had to have a dream to grasp what Jesus was replacing. A little of that is revealed in the rest of the verses in Matthew 5 that you DIDN'T include. Can you understand that not only did the 10 Commandments NOT pass, but under Jesus' New Agreement that they were made more strict?
Jesus continued to attend the Temple after this. He observed the holy days. It wasn't until the Last Supper and Crucifixion that He gave us the replacement for the Temple sacrifices - His own flesh & blood.
Jesus knows we can't keep the new laws ourselves much less the old. We need Him, we need his sacraments.
