That first-hand knowledge was shared by Their immediate followers, who carried on the teaching of the system after the Teacher had withdrawn.

And it matters not what religion you take, living or dead, you will find it equally true, that phenomena were common in the earlier days of the teaching of that religion.
Now let me take two typical religions, one Eastern and one Western, with regard to the continuance of the phenomena of the earlier days--the Hindu religion in the East for the Eastern example, and the Roman Catholic Church in the West for the Western example.

In both these great religious movements we find a continuance of phenomena; neither Hinduism as typical of Eastern teaching, nor Roman Catholicism as the most widespread form of Christianity in the West, has ever taken up the position that the life which showed itself through the earlier teachers was cut off and no longer irrigated the fields of the religion.

On the contrary, you find both these typical religions claiming continuity of life and of knowledge.

Amongst the Hindus it is a commonplace to assert the possibilities of yoga, that a man can now, as much as in the days of the Manu or of the great Rishis, do what They did, can free himself from the physical body, can travel into other worlds of the systems, can acquaint himself with the forces and objects of those worlds, and carry on as definite a study of the Not-Self in those worlds, as anyone who wishes to do so may carry on a definite study of the Not-Self in the physical world.