1 Corinthians 1:10  Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment.

Galatians 5:14-15
14  For all the law is fulfilled in one word, even in this; Thou shalt love thy neighbour as thyself.
15  But if ye bite and devour one another, take heed that ye be not consumed one of another.

Luke 6:41-42
41  And why beholdest thou the mote that is in thy brother's eye, but perceivest not the beam that is in thine own eye?
42  Either how canst thou say to thy brother, Brother, let me pull out the mote that is in thine eye, when thou thyself beholdest not the beam that is in thine own eye? Thou hypocrite, cast out first the beam out of thine own eye, and then shalt thou see clearly to pull out the mote that is in thy brother's eye.

Mark 3:25  And if a house be divided against itself, that house cannot stand.