4:1-5 The Holy Spirit, both in the Old and the New Testament, spoke of a general turning from the faith of Christ, and the pure worship of God. This should come during the Christian dispensation, for those are called the latter days. False teachers forbid as evil what God has allowed, and command as a duty what he has left indifferent. We find exercise for watchfulness and self-denial, in attending to the requirements of God's law, without being tasked to imaginary duties, which reject what he has allowed. But nothing justifies an intemperate or improper use of things; and nothing will be good to us, unless we seek by prayer for the Lord's blessing upon it.
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 (1Ti 1:5); so hypocrisy (that is, unbelief, Mt 24:5, 51; compare Lu 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; 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 (2Ti 2:19), so "a brand" in a bad sense. The image is taken from the branding of criminals.