Pope Francis called on Catholics to continue living the "Gospel of Mercy," saying it's an open book for them to record their good deeds.

The Pope made the remarks on Divine Mercy Sunday, explaining that the Gospel started by Jesus and the apostles is still unfinished, the Catholic News Agency reported.

"The Gospel is the book of God's mercy, to be read and reread, because everything that Jesus said and did is an expression of the Father's mercy," Pope Francis said on Sunday.

He said at the end of the day's Gospel reading from John, the evangelist expressed that while Jesus Christ carried out many signs in the presence of his disciples, not all of them were written down.

As such, "the Gospel of mercy remains an open book, in which the signs of Christ's disciples, which are concrete acts of love and the best witness to mercy, continue to be written," the Pope said.

He said "we are all called to become living writers of the Gospel" by doing corporal and spiritual works of mercy that symbolise Christian life.

"By means of these simple yet powerful gestures, even when unseen, we can accompany the needy, bringing God's tenderness and consolation," he said.

The Pope said to be an apostle means touching and soothing the wounds that afflict the bodies and souls of many.

Pope Francis prayed that all would receive the grace "to never grow tired of drawing from the well of the Father's mercy and bringing it to the world."

During the feast of Divine Mercy on Saturday, Pope Francis said, "The more we receive, the more we are called to share it with others; it cannot be kept hidden or kept only for ourselves."

"It is something which burns within our hearts, driving us to love, thus recognising the face of Jesus Christ, above all in those who are most distant, weak, alone, confused and marginalised," he said.

The feast is celebrated on the first Sunday after Easter every year and it was instituted by St. John Paul II in 2000.

"Mercy seeks out the lost sheep, and when one is found, a contagious joy overflows. Mercy knows how to look into the eyes of every person; each one is precious, for each one is unique," Pope Francis said during his address.

He said God never tires of showing mercy on everybody and the chance to receive mercy should never be taken for granted.

"It is something always new, which inspires awe and wonder as we see God's immense creativity in the ways he comes to meet us," he said.