One of the great things about the Sermon on the Mount is that you can see it within the context of the entire Gospel according to Matthew, but you can also look at one word and see it within the context of the entire scriptures.
An easy word to do that with is ‘righteousness’. It’s essentially throughout the entire bible. In the text from the Sermon on the Mount, Jesus says our righteousness has to surpass that of the scribes and Pharisees (5:20). But that’s not too hard if God is in control of that word—which he is from the beginning. (And Abraham believed the Lord, and the Lord counted it to him as righteousness—Genesis 15:6.) The Lord, the Righteous One, gives that righteousness out, where and when it pleases him.
It’s not too easy to see the word ‘think’ in context with all of scripture. It’s not a bad thing to do though. The human race ends up thinking a lot. In the text we are not supposed to think that Jesus came to do away with the Law and the Prophets. That word’s use within all of Matthew is pretty distinctive—an interesting characteristic of this very ‘human’ gospel account.
In that command, the verb ‘to think’ is given as follows in one of the dictionaries (BDAG): ‘To form an idea about something, but with some suggestion of tentativeness or refraining from a definitive statement.’
In our era, you have probably heard it said that you need to exaggerate to be heard. Perhaps you have heard of people encouraging others to speak up with confidence, even if they have reservations about what they believe. This is not new. And those things that are true and lasting will prove themselves in the end.
We are constantly forming ideas. We are in a constant state of tentativeness. That’s this life. And that’s usually pretty depressing.
That’s why Jesus came down. We needed a savior. We needed a savior, even from our own thoughts. And we have that—and more—in Jesus.