Let's try again.
"Then he goes on in the very next verse to explain that the law is not fulfilled "until heaven and earth disappear," and that until God ends the world "not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law." "
That's not what He said though. Not exactly anyway.
17 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.
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.
He doesn't say that heaven and earth has to pass before it can be fulfilled. Rather that it will all be fulfilled - none of it left undone or skipped over. It was to be in full effect till all be fulfilled, till the end. It was fulfilled. Nothing about it was left out, no I's left undotted, no T's left uncrossed. All of it was completed by Him coming here and giving His life on the Cross. That was the fulfilling of that old law, as is easily seen through studying and rightly dividing the Word. When Jesus died on that Cross it fulfilled ALL that was left of the law. It was completed before the end of time, and as such His statement in verse 18 was true. It may not have been the end of time, but it doesn't matter because nothing passed from that law, it having been completed.
Because He stated it the way that He did, it leaves much that could still happen after heaven and earth pass. One possibility being that any number of commandments, or descriptions could be removed from those old laws, and thereby clearing, or excusing, some from past times sins. There's much that's left of possibilities, because od those statements.
That's not the issue though. What is, is if the law could be fulfilled prior to the end. There's nothing He said that would prevent it from being fulfilled, and fulfill it he did. While He lived He was under that law and therefore taught those, at that time, to obey the old law. He too obeyed it. As for His new covenant, He only taught of it to come. He didn't teach that any, of that time, should follow it. Rather they were to follow it upon it being put into place. It couldn't be until the old was ended. That old being done away w/upon His death, the new was established upon Christ having risen. There is no old law to follow as it has been fulfilled. Nothing was left undone either. Now it's complete and there can be the passing of heaven and earth, w/out there being a conflict between the two.
Col 2:14 Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;