Feast of St. Augustine
Saint Paul the Apostle teaches in his Epistle to the Galatians that those who do uncleanness… shall not obtain the kingdom of God (5.19,21). Of Old, the unclean man refers to every leper, and whosoever hath an issue of seed [semen], or is defiled by the dead (Num. 5.2). They were excluded from the camp of the Hebrews – in the midst of which was the presence of God through the Ark of the Covenant, a figure fulfilled by the tabernacle placed at the middle of our traditionally exalted Catholic altar. Therefore, in the New Dispensation by the Giver of Life, those from whom the seed of copulation goeth out (Lev. 15.16) into his wife are not condemned unless they hinder [“contraception”] the natural end of issuing semen – that is, the bringing forth of children – and waste the seed of life (cf., Gen. 38.9-10); also not condemned are those who hath an issue of seed out of nocturnal phantasm (cf., Deut. 23.10) unless upon being awakened they fully consented to its concomitant sexual pleasure.
See also: “Vade Retro Satana!” (On Lust and the Vice of Impurity)