The Holy Father began by reflecting on the first reading from the prophet Isaiah in which he calls "the princes of Sodom" and the "people of Gomorrah" to turn from their evil ways.
"Wash yourselves clean! Put away your misdeeds from before my eyes; cease doing evil; learn to do good. Make justice your aim: redress the wronged, hear the orphan’s plea, defend the widow," the reading states.
According to Vatican Radio, the Holy Father told those present that the reading is an invitation from God to conversion by learning to do right.
"You cannot remove the filth of the heart as you would remove a stain: we go to the dry cleaner and leave cleansed," he said. "This filth is removed by 'doing': taking a different path, a different path from that of evil. Learn to do right! That is, the path of doing good."
Citing the first reading, the Holy Father said that in order to good one must protect those most in need which will allow one to "cleanse your heart." Those whose hearts are cleansed, he stressed, are forgiven by God.
"If you do this, if you take this path to which I invite you - the Lord tells us - 'though your sins be as scarlet, they shall be as white as snow'. It is an exaggeration, the Lord exaggerates: but it is the truth!" he exclaimed. "The Lord gives us the gift of His forgiveness. The Lord forgives generously. 'I forgive you this much, then we'll see about the rest....' No, no! The Lord always forgives everything! Everything! But if you want to be forgiven, you must set out on the path of doing good. This is the gift!'"
The 78 year old Pontiff went on to reflect on today's Gospel in which Christ denounces the hypocrisy of the Pharisees, who like many today "say all the right things, but do the exact opposite."
"They pretend to convert, but their heart is a lie: they are liars! It 'a lie ... Their heart does not belong to the Lord; their heart belongs to the father of all lies, Satan. And this is fake holiness," he said.
"Jesus preferred sinners a thousand times to these. Why? Because sinners told the truth about themselves. 'Get away from me, Lord, I am a sinner!': Peter once said. One of those [the hypocrites] never says that! 'Thank you Lord, that I am not a sinner, that I am righteous."
Concluding his homily, Pope Francis called on the faithful to reflect during this time of Lent on conversion, forgiveness and to beware of "pretending to convert, while choosing the path of hypocrisy."