Pope Francis took possession of his cathedral as Bishop of Rome and spoke about how God's mercy and patience should challenge everyone to find the courage to accept his love.

"Dear brothers and sisters," he began his homily, "let us be enveloped by the mercy of God; let us trust in his patience, which always gives us more time. Let us find the courage to return to his house, to dwell in his loving wounds, allowing ourselves be loved by him and to encounter his mercy in the sacraments."

The Pope's installation in the "cathedra" or seat in St. John Lateran Basilica at around 5:30 p.m. on April 7 signaled that he is now officially taking up his duties as the Bishop of Rome.

When he arrived at the basilica, Pope Francis first participated in the renaming of a small section of the square outside of the church, which went from being St. John Lateran to Blessed John Paul II Square.

He then entered the basilica and greeted everyone as he walked down the aisles. He also individually greeted disabled people in what has become a trademark of his encounters with crowds.

In his homily, Pope Francis focused on the theme of God's mercy, a fitting motif for today's Feast of Divine Mercy.

"What a beautiful truth of faith this is for our lives: the mercy of God! God's love for us is so great, so deep; it is an unfailing love, one which always takes us by the hand and supports us, lifts us up and leads us on," he said.

Noting that the Gospel reading for today is about St. Thomas seeing Jesus after his resurrection and how when he first heard the news of his rising from the dead he did not believe it.

"And how does Jesus react? With patience: Jesus does not abandon Thomas in his stubborn unbelief; he gives him a week's time, he does not close the door, he waits.

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"And Thomas acknowledges his own poverty, his little faith. 'My Lord and my God!': with this simple yet faith-filled invocation, he responds to Jesus' patience," the Pope observed.

"He lets himself be enveloped by divine mercy; he sees it before his eyes, in the wounds of Christ's hands and feet and in his open side, and he discovers trust: he is a new man, no longer an unbeliever, but a believer."

"Brothers and sisters," Pope Francis urged, "let us never lose trust in the patience and mercy of God!"

He also pointed to the disciples on the road to Emmaus as a good example of "God's way of doing things."

God "is not impatient like us, who often want everything all at once, even in our dealings with other people," the Pope said after recalling how Jesus walked with the despairing disciples, patiently explained the Scriptures and gave them the Eucharist.

"God is patient with us because he loves us, and those who love are able to understand, to hope, to inspire confidence; they do not give up, they do not burn bridges, they are able to forgive," he added.

Pope Francis stressed one final point in his homily: "God's patience has to call forth in us the courage to return to him, however many mistakes and sins there may be in our life."

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"Jesus tells Thomas to put his hand in the wounds of his hands and his feet, and in his side. We too can enter into the wounds of Jesus, we can actually touch him. This happens every time that we receive the sacraments with faith," he underscored.

The Pope recalled how he has heard many people say, "'Father, I have many sins;' and I have always pleaded: 'Don't be afraid, go to him, he is waiting for you, he will take care of everything.'"

"We hear many offers from the world around us," Pope Francis said, "but let us take up God's offer instead: his is a caress of love. … even if we are sinners, we are what is closest to his heart."

As he came to the end of his homily, the Pope said that in his own life he has "so often seen God's merciful countenance, his patience; I have also seen so many people find the courage to enter the wounds of Jesus by saying to him: Lord, I am here, accept my poverty, hide my sin in your wounds, wash it away with your blood."

"And I have always seen that God did just this – he accepted them, consoled them, cleansed them, and loved them."