Jesus sternly warned them, saying, "See that no one knows it." But when they had departed, they spread the news about Him in all that country. (Matthew 9:30-31)
You would think that after being healed of blindness that the ones receiving their sight would be obedient to the one who healed them. I do not know why Jesus "sternly" instructed them not to tell anybody. Nevertheless, they surely would have proven themselves wiser by heeding His command. Most likely they justified themselves thinking that such a good deed needed to be repeated. We will never know in this life what could have been accomplished or what further works Jesus could have done if these two once blind men would have obeyed Him. The lesson is clear, we may not always understand authority, but we ought to obey it. The only exception would be a higher authority overriding a subordinate authority. And, "There is no authority except from God, and the authorities that exist are appointed by God."