Purification is regarded as the most acceptable means for attaining the nearness unto God and the most meritorious of all deed

The Báb, Selections from the Writings of the Báb, p. 126

. . . sifting out the weak and raising up the strong in that constant purification of the ranks of the faithful which takes place in the course of the growth of this World Community.

Custodians, Ministry of the Custodians, p. 351