What is unity?

In the Tablet of Ittihad, Bahá'u'lláh describes in some detail several features of unity. He states that unity in the first place is the unity of religion, meaning that people must follow the same religion which is His Faith in this day. He declares that when the majority of the people in a country embrace His Cause, then the government will be able to put into practice His teachings and commandments. He asserts that in past dispensations such a unity has always brought victory to the Cause of God.

https://bahai-library.com/rev_bahaullah_4/taherzadeh_revelation_bahaullah_4.txt