“We venture to make the assertion that there is but one sin: IGNORANCE, and but one salvation: APPLIED KNOWLEDGE.”
The Rosicrucian Mysteries (1911)
Help us to complete the source, original and additional information
Max Heindel 8
American asrologer and occultist 1865–1919Related quotes
Source: The Meaning of God in Human Experience (1912), Ch. XIV : The Need of an Absolute, p. 198.

Muhammad Kulayni, Usūl al-Kāfī - The Book of Intellect and Ignorance.
Regarding Knowledge & Wisdom, General

“There is only one good, knowledge, and one evil, ignorance.”
Socrates II: xxxi http://www.perseus.tufts.edu/hopper/text?doc=D.+L.+2.5.31&fromdoc=Perseus%3Atext%3A1999.01.0257#note-link14. Original Greek: ἓν μόνον ἀγαθὸν εἶναι, τὴν ἐπιστήμην, καὶ ἓν μόνον κακόν, τὴν ἀμαθίαν
Diogenes Laertius
Variant: The only good is knowledge and the only evil is ignorance.

“Real knowledge is to know the extent of one's ignorance.”

“WE ARE COMPELLED, OUR FAITH URGING us, to believe and to hold—and we do firmly believe and simply confess—that there is one holy Catholic and Apostolic Church, outside of which there is neither salvation nor remission of sins”
Unam sanctam ecclesiam catholicam et ipsam apostolicam urgente fide credere cogimur et tenere, nosque hanc frmiter credimus et simpliciter confitemur, extra quam nec salus est, nec remissio peccatorum,
Unam sanctam (1302)

“He said that there was one only good, namely, knowledge; and one only evil, namely, ignorance.”
Socrates, 14.
The Lives and Opinions of Eminent Philosophers (c. 200 A.D.), Book 2: Socrates, his predecessors and followers