Equality of humans

When in the middle east, the west and the rest of asia slavery, varna class and race discrimination was rife and respect between the different classes and caste was at a peak, Guru Nanak preached against discrimination and prejudices due to race, caste, status, etc. He said See the brotherhood of all mankind as the highest order of Yogis; conquer your own mind, and conquer the world. also There is one awareness among all created beings. and finally One who recognizes the One Lord among all beings does not talk of ego. He urges all the peoples of the world to conquer their minds to these evil practises. All human beings had the light of the Lord and were the same only by subduing ones pride and ego could one see this light in all.