Please go to the link below and watch Sheikh Yusuf Estes explain how bad it is to be divided into sects.
Sheikh Yusuf Estes used to be a Christian minister in the U.S. before he converted to Islam. He became a Muslim when he tried to convert someone else to Christianity. He is known worldwide for his lectures and he has brought thousands of people to Islam Masha'Allah.
please go to the link below to watch him tell his story of how be became a Muslim. It's very interesting.
your gonna have to click on part 2 when part 1 is over and so on.
The Quran says this about sects
[6:159] Those who divide themselves into sects do not belong with you. Their
judgment rests with GOD, then He will inform them of everything they had done.
[30:32] (Do not fall in idol worship,) like those who divide their religion
into sects; each party rejoicing with what they have.
[42:13] He decreed for you the same religion decreed for Noah, and what we
inspired to you, and what we decreed for Abraham, Moses, and Jesus: "You shall
uphold this one religion, and do not divide it." The idol worshipers will
greatly resent what you invite them to do. GOD redeems to Himself whomever He
wills; He guides to Himself only those who totally submit. [42:14]
Ironically, they broke up into sects only after the knowledge had come to them,
due to jealousy and resentment among themselves. If it were not for a
predetermined decision from your Lord to respite them for a definite interim,
they would have been judged immediately. Indeed, the later generations who
inherited the scripture are full of doubts.