Notice the verse before and the verse after Matt 5:19
Matt 5:18
For I tell you truly, until heaven and earth pass away, not a single jot, not a stroke of a pen, will disappear from the Law until everything is accomplished.
Matt 5:20
For I tell you that unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.
The scribes and Pharisees do and teach (the)
them in verse 19, and Jesus says that your righteousness must exceed theirs to enter the kingdom of heaven.
Now back up one more verse where Jesus declares the reason He came.
Matt 5:17
Do not think that I have come to abolish the Law or the Prophets. I have not come to abolish them, but to fulfill them.
Jesus claim to exceed the righteousness of the scribes and Pharisees. They did and taught them, but not one had ever been able to successfully fulfill them.
These verses are written in regard to the context of
The Fulfillment of the Law.
Luke 16:17 declares reflects what Matt 5:18 says in regard to the Law and the Prophets
But it is easier for heaven and earth to pass away than for a single stroke of a pen to drop out of the Law.
Considering Jesus' declaration, "It is finished," in contrast to the concept that the passing away of heaven and earth being the condition that a single jot or stroke of the pen from the Law will disappear, as it's easier for that to happen than for a single stroke of a pen to drop out of the Law... one might think that Jesus came with an intention to dissolve the heaven and the earth....