In the Gospel of Luke 10:25-41, Jesus was interviewed by a lawyer who wanted to know what is necessary for eternal life in Heaven. To begin his answer, Jesus asked the lawyer what the Mosaic Law said about it. When the lawyer quoted the basic law of loving God with all your heart, with all your mind and all your strength and the parallel law of loving one's neighbour as yourself, Jesus said that would be all that is necessary for Heaven.
When the lawyer asked Jesus to define what he meant by neighbour, Jesus responded with a parable about a Jewish traveler who was attacked, robbed and left for dead by the side of a road. Later, a priest saw the stricken figure and avoided him. Later still, a Levite saw the man and ignored him as well. Then a Samaritan passed by, and despite the mutual antipathy between his and the Jewish populations, immediately rendered assistance by giving him first aid and taking him to an inn to recover while promising to cover the expenses.
At the conclusion of the story, Jesus asked the lawyer of the three passers-by, who was the stricken man's neighbour? When the lawyer responded that it was the man who helped him, Jesus challenged him to do likewise.
This parable is one of the most famous in the Bible and its influence is such that to be called a Samaritan in Western culture today is to be described as a genorous person who is ready to provide aid to people in distress without hesitation. In many English-speaking countries, a Good Samaritan law exists to protect from liability those who choose to aid people who are seriously ill or injured.