By its nature, sin perpetuates itself by making us insensitive or blind to sin. Consequently, the more we sin, the more unaware we become of our desperate need to repent. This sin-blindness is more difficult to remove than physical blindness. Only God and those speaking in God's name, that is, the prophets, have the power to break through sin-blindness.
The prophet Isaiah tried to shock the people into a renewed sense of sin by calling them "princes of Sodom" and "people of Gomorrah" (Is 1:10). This is like calling the people of today Nazis, terrorists, and members of the Mafia. Isaiah then announced that God was disgusted with the Israelites' sacrifices, worship services and prayers (see Is 1:11-15). Isaiah's outrageous comments were intended to break through the Israelites' sin-blindedness. However, Isaiah's prophecies were not successful at the time.
Moses prophesied that there would some day come the ultimate Prophet (Dt 18:15; Acts 3:22), Who would break through sin-blindness. Jesus is this Prophet. He is also Lord and God. His words and the words of His body, the Church, are "spirit and life" (Jn 6:63). These words lay bare the secrets of our hearts (see 1 Cor 14:25; Lk 2:35). They break through sin-blindness and lead us to repentance. Listen to Jesus and His body, the Church, or you will die blinded by and to sin.