God looks beyond appearances and into people's hearts and knows that there is no saint without a past, Pope Francis has said."The Lord looks into the heart," Pope Francis said in a sermon at the Vatican's Santa Marta hotel, where he lives."We are often the slaves of appearances and allow ourselves to pursue appearances: But God know the truth," the Pope said.The life of the biblical King David showed that even in the lives of the saints there are temptations and sins, the pontiff said."He became a saint after living a long life during which he sinned," Francis said, describing David as "a great sinner but a repentant one"."The life of this man moves me -- it makes us think of our own lives," he said."It makes me think that during the Christian journey, the journey the Lord has invited us to undertake, there is no saint without a past and so no sinner without a future," he said.