This scripture on love comes from the well know sermon on the mount. The Savior went up to a certain mountain and His apostles followed Him there. On the mountain the Savior taught His disciples many gospel principles. One of the things that he taught was about love. This is one of the most quotes scriptures on love within the Bible.
44 But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
45 That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.
46 For if ye love them which love you, what reward have ye? do not even the publicans the same?
47 And if ye salute your brethren only, what do ye more than others? do not even the publicans so?