Baha'i teaching work cannot be compared with other social works

"Your work to improve the health of people is a meritorious way of serving mankind, but it can never be compared with the work of illumining the souls and minds of men with the Light of Bahá’u’lláh. The people of the world are teeming millions, the Bahá’ís only a handful, yet they are the precious leaven that must leaven the lump."

(From a letter written on behalf of Shoghi Effendi to an individual believer, May 8, 1942)