1-е Тимофею 4:2

Rather translate, "Through (literally, 'in'; the element in which the apostasy has place) the hypocrisy of lying speakers"; this expresses the means through which "some shall (be led to) depart from the faith," namely, the reigned sanctity of the seducers (compare "deceivers," Tit 1:10). having their conscience seared--Greek, "having their own conscience," &c., that is, not only "speaking lies" to others, but also having their own conscience seared. Professing to lead others to holiness, their own conscience is all the while defiled. Bad consciences always have recourse to hypocrisy. As faith and a good conscience are joined (Ti1 1:5); so hypocrisy (that is, unbelief, Mat 24:5, Mat 24:51; compare Luk 12:46) and a bad conscience here. THEODORET explains like English Version, "seared," as implying their extreme insensibility; the effect of cauterizing being to deaden sensation. The Greek, however, primarily means "branded" with the consciousness of crimes committed against their better knowledge and conscience, like so many scars burnt in by a branding iron: Compare Tit 1:15; Tit 3:11, "condemned of himself." They are conscious of the brand within, and yet with a hypocritical show of sanctity, they strive to seduce others. As "a seal" is used in a good sense (Ti2 2:19), so "a brand" in a bad sense. The image is taken from the branding of criminals.

Paul here foretels, I. A dreadful apostasy (Ti1 4:1-3). II. He treats of Christian liberty (Ti1 4:4, Ti1 4:5). III. He gives Timothy divers directions with respect to himself, his doctrine, and the people under his care (Ti1 4:6 to the end)

4:2 Consciences that are dead either don’t function or function wickedly, rendering judgments that oppose the truth of the gospel (see also Titus 1:15; Rom 1:28-32).