What does Matthew 9:30 mean?

After asking two blind men about their faith in Him, Jesus has touched their eyes and healed them "according to your faith." It's not that these two had exceptionally pious lives, or that they were especially worthy of healing. It's that their faith was placed in the right person: Jesus the Messiah. That faith was effective because Jesus is powerful and trustworthy (Matthew 9:27–29).

Now Jesus tells the two men—sternly, no less—to see that no one knows about what He has done for them. This is the second time Matthew mentions Jesus giving this kind of instruction to someone newly healed (Matthew 8:4). According to Mark, Jesus had given the same command to Jairus's family (Mark 5:43), with similar results (Matthew 9:25–26). He seems to be attempting to keep His fame and reputation as the Messiah from spreading too quickly. It has not yet worked. One would imagine it would be difficult for two formerly blind men to hide the fact that they could now see. The following verse reveals that they do not seem to attempt it.