Are Jesus and Satan brothers?
No, Jesus and Satan are not brothers. Jesus is God and Satan is one of His creations. Not only are Jesus and Satan not brothers, they are as different as night is from day. Jesus is God incarnate—eternal, all knowing and all powerful while Satan is a fallen angel that was created by God for God’s purposes. The teaching that Jesus and Satan are “spirit brothers” is one of the many false teachings of the Mormons (Latter Day Saints), and to some degree also the Jehovah’s Witnesses. Both of these groups are properly labeled as cults because they deny essential Christian doctrine. While they use Christian terms such as Jesus, God and salvation, they have heretical views and teachings on the most basic and essential Christian doctrines. (Please note that most Mormons today will vehemently deny that they believe Jesus and Satan are brothers. However, this teaching was most definitely a belief of the early Mormons).
The teaching that Jesus and Satan are “spirit brothers” is born out of the Mormons’ misunderstanding and distortion of Scripture as well as some of the extra-biblical teachings they consider to be authoritative. Simply put there is no way you can read the Bible using any type of sound hermeneutical principles and come away with the idea that Jesus and Satan are “spiritual brothers.” The Scriptures are very clear that Jesus is fully God, not some type of lesser god as the Mormons or other cults believe. The Scriptures are also very clear that God is transcendent above His creation which simply means that there is no comparison between Christ the Creator and Satan His creation.
Read more: http://www.gotquestions.org/Jesus-Satan-brothers.html