An important reason of the popularity of Bhakti movement was that they challenged the caste system and the superiority of the Brahmanas. They welcomed the ideas of equality and brotherhood which the Sufi saints also preached. People were no longer satisfied with the old religion. They wanted a religion which could satisfy both their rationality as well as emotions.
In northern India, it developed into two streams, nirguna bhakti and saguna bhakti. The nirguna bhaktas were devotees of a formless God even while calling him variously as Rama, Govinda, Hari or Raghunatha. The most conspicuous among them were Kabir and Nanak. The saguna bhaktas were devotees of Rama, the son of Dasharatha, or Krishna, the son of Devaki and Vasudeva. Some of the best examples of Saguna bhaktas were Tulsidas, who idolised Rama in his famous Ramcharita Manas, and Surdas, who sang praises of Krishna in his famous Sursagar. Raskhan, a Muslim poet, who was a devotee of Lord Krishna, also belonged to this tradition.
The first important feature of bhakti movement was the concept of oneness of God and brotherhood of all human beings. It did not discriminate against anyone on the basis of caste or gender. Its second important feature was surrender into God, who is all pervasive and capable of solving the problems of the devotees. The third important feature of bhakti was an intense personal devotion to God with an emphasis on a good moral life. It was felt that chanting the name of God constantly purified the soul and prepared one for His grace. A true devotee does not want heaven or moksha. He only wants to chant the Lord’s name and be born again and again to sing His praise.