"Now it happened on another Sabbath, also, that He [Jesus] entered the synagogue and taught.
And a man was there whose right hand was withered.
So the scribes and Pharisees watched Him closely, whether He would heal on the Sabbath, that they might find an accusation against Him.
But He knew their thoughts, and said to the man who had the withered hand 'Arise and stand here.'
Then Jesus said to them, 'I will ask you one thing is it lawful on the Sabbath to do good or to do evil, to save life or to destroy?
And when He had looked around at them all, He said to the man, 'Stretch out your hand.'
And he did so, and his hand was restore as whole as the other."
Matthew 12:9-13
Mark 3:1-5
The right hand represented honor and strength.
To restore the man's hand would restore the honor and strength of His life.
Jesus demonstrated that it is always lawful to do good and heal. In fact, it would be evil not to.
By doing this, Jesus reveals that it is God's will to heal, for God is not evil.