Christians believe that there is only one God, whom they call Father as Jesus Christ taught them. They recognise Jesus as the son of God and believe God functions as a Trinity. Christians believe in the Trinity - that is, in God as Father, Son and Holy Spirit. Jesus Christ taught that he was Son of God. His teachings can be summarised, briefly as the love of God and love of one's neighbour. Jesus said that he had come to fulfill God's law rather than teach it. These days, the word saint is most commonly used to refer to a Christian who has lived a particularly good and holy life on earth, and with whom miracles are claimed to have been associated after their death.