If they arise to teach My Cause,

 The voice of the Divine Herald, proceeding out of the throne of God, declareth: 

O ye My loved ones! Suffer not the hem of My sacred vesture to be smirched and mired with the things of this world, and follow not the promptings of your evil and corrupt desires. The Day Star of Divine Revelation, that shineth in the plenitude of its glory in the heaven of this Prison, beareth Me witness. They whose hearts are turned towards Him Who is the Object of the adoration of the entire creation must needs, in this  Day, pass beyond and be sanctified from all created things, visible and invisible.
If they arise to teach My Cause, they must let the breath of Him Who is the Unconstrained, stir them and must spread it abroad on the earth with high resolve, with minds that are wholly centered in Him, and with hearts that are completely detached from and independent of all things, and with souls that are sanctified from the world and its vanities. It behoveth them to choose as the best provision for their journey reliance upon God, and to clothe themselves with the love of their Lord, the Most Exalted, the All-Glorious. If they do so, their words shall influence their hearers.

Gleanings From the Writings of Bahá’u’lláh