They Asked for Mercy and got Grace
Blindness is always a major problem. But in Jesus' day it meant no education, no income (except from begging) and social exclusion. Blind people were considered to be cursed because of their own sin or the sins of their parents (John 9:2). So these two blind men called out for mercy. They felt the shroud of assumed guilt upon them and they knew that they had no right to anything. But they begged Jesus to deliver them from the curse of their blindness.
We do not know how they were allowed to enter the house, but they did. It seems to have been a more private conversation witnessed by the disciples. Jesus asked them if they had faith in His ability to heal them - a specific question to stir them into confessing whatever faith they had. The answer was a confident, 'Yes'! Jesus simply reached out and touched their eyes and linked their healing to their faith in Him. Their restored sight was proof of their faith, and proof of Jesus' divine power.
But Jesus' enemies were searching for whatever evidence they could find to discredit Him. As the healing of blind people was a Messianic sign (Isaiah 61:1), the Pharisees were eager to use the healing to denounce the Lord. So He instructed the previously-blind men not to boast about their newfound sight. But they could not contain their joy, and it soon became common knowledge.
Mercy spares us from the punishment we deserve because of our sins; but grace gives us God's blessing and provision through God's love, even though we do not deserve it. When people come to Jesus, however great their sin and shame, He extends His mercy and then applies His grace: and all of it totally undeserved. There is no other way we can be accepted by God and no other way to receive His favour - except by coming to Him in faith that he can remove our shame and restore our function. Think, today, about a friend of colleague who feels rejected because of their circumstances; and ask them to put their trust in Jesus.