
“For the spiritual power of a sacrament is like light in this way: it is both received pure by those to be enlightened, and if it passes through the impure it is not defiled.”
Spiritalis enim virtus Sacramenti ita est ut lux: et ab illuminandis pura excipitur, et si per immundos transeat, non inquinatur.
Tractates on the Gospel of John; tractate V on John 1:33, §15; translation by R. Willems
Compare:
The sun, too, shines into cesspools and is not polluted.
Diogenes Laërtius, Lib. vi. section 63
A very weighty argument is this — namely, that neither does the light which descends from thence, chiefly upon the world, mix itself with anything, nor admit of dirtiness or pollution, but remains entirely, and in all things that are, free from defilement, admixture, and suffering.
Julian, in Upon the Sovereign Sun http://www.tertullian.org/fathers/julian_apostate_1_sun.htm, (c. December 362), as translated by C. W. King in Julian the Emperor (1888) - Full text online http://www.archive.org/details/julianemperorco00juligoog
The sun, which passeth through pollutions and itself remains as pure as before.
Francis Bacon, Advancement of Learning, Book II (1605)