We must remember that Luke is writing this gospel account to his friend named Theophilus. Luke is convinced that Jesus is the promised Messiah sent by God. His account of many of the things that Jesus did is to convince his friend so that his friend will believe in Jesus.
In chapter 7, we have Luke recording many miracles that Jesus performed that included raising one from the dead. Jesus proved through these miracles that He was the Son Of God. Jesus also proved that He was the Messiah when He forgave the sins of a woman who washed His feet. Only God can forgive sins. Jesus told the woman that she could go in peace because her faith had saved her. Only through faith in Jesus can we find salvation and peace!