What was the prophecy of the The Holy Prophet about Muslims being divided into sects?
In the name of Allah, the Gracious, the Merciful
There is none worthy of worship except Allah, Muhammad is the Messenger of Allah
Muslims who believe in the Messiah,
Hazrat Mirza Ghulam Ahmad Qadiani (as)

What was the prophecy of the The Holy Prophet about Muslims being divided into sects?

More than 1400 years ago, the Holy Prophet (peace be upon him) made a prophecy that said,

“My people will be divided into 73 sections, all of them will be in the fire except one.” The companions asked, ‘Who are they O Messenger of Allah,’ Holy Prophet (peace be upon him) said, “They are those who will be like me and my companions.” (Trimizi, Kitabul Eeman).

How does one identify the true sect?

As previously mentioned, the Holy Prophet(sa) had prophesized that his followers would be divided into 73 sects, and all would be in the fire except one. When asked by his companions, how one could recognize the true sect, he replied that they will follow in mine and my followers footsteps. The persecution of the Holy Prophet(sa) and his companions was very severe. They were victims of public stoning because of their beliefs, they weren’t allowed to build mosques nor pray. They weren’t allowed to perform Hajj or identify themselves as Muslims.

This kind of treatment has been shown to every generation so far since the foundation of Ahmadiyya Movement in Islam. Ahmadis in most Muslim countries are not allowed to preach openly, are not allowed to build mosques or call their buildings mosques, are not allowed to pray openly and are not allowed to perform Hajj.

The government of Pakistan and the leaders of all the rest of 72 sects of Islam (other than Ahmadi Muslims) clearly distinguished the identity of the true sect when they collectively signed legislation in 1974 that declared all Ahmadis a non-Muslim minority in Pakistan. This decision, however, did ironically provide an interesting, if not unique, distinction of one group of Muslims from the other 72 sects fulfilling the prophecy of Holy Prophet(sa).