Ramakrishna had no formal education, but his spiritual realization was immense.
His power of explaining deep philosophical points in simple and easy words and metaphors was astounding.
He strongly believed that all religions were equally valid and ultimately led to the same goal.
Thus Ramakrishna inspired a Muslim to be a true Muslim, and a Christian to be faithful to Christ. Under his inspiration the Hindus regained their faith in Hinduism.
This was a great idea that Ramakrishna set forth before the Indian people Ramakrishna, however, could not build up an all-India movement by his teaching.
This task was later on completed by his great disciple, Swami Vivekananda.