Pope Francis has delivered a fiery sermon against corruption, quoting a passage from the Bible in which Jesus said some sinners deserve to be tied to a rock and thrown into the sea.

In one of his strongest-worded homilies since he was elected in March, the Argentinean pontiff said Christians who lead “a double life” by giving money to the Church while stealing from the state are sinners who deserve to be punished.

Quoting from the Gospel of St Luke in the New Testament, he said “Jesus says: It would be better for him if a millstone were put around his neck and he be thrown into the sea.”

While he did not allude directly to corruption within the Catholic Church, his remarks come just days after a scandal erupted inside an ancient religious order linked to the Vatican, and as he forges ahead with a determined effort to root out cronyism within the Holy See and financial irregularities in the scandal-tainted Vatican bank.

The Pope described people engaged in corruption as “whitewashed tombs”, explaining that “they appear beautiful from the outside, but inside they are full of dead bones and putrefaction.” A life based on corruption is “varnished putrefaction”, the Pope said.