Faith comes only as God's sovereign gift, and God has immutably decided to withhold
this gift from the non-elect, but rather to actively harden them; therefore, to sincerely
offer salvation to the non-elect as if God desires them to be saved and as if it is possible for them to be saved would be to lie to them in God's name. There is no real or sincere offer of salvation to the non-elect, but only a real and serious command that they can never obey, and one that God will enforce against them with hellfire.
Again, this does not prevent us from indiscriminately preaching the gospel to all men, since it is neither our right nor duty to pick out the elect and preach only to them, or to pick out the non-elect and exclude them. The point is that we must not present the gospel as a sincere offer to all, as if God's "desire" can differ from his decree, as if God could or would decree against his "desire," and as if it is possible for even the non-elect to be saved. Rather, we must present the gospel as a serious command to all, as if it is required of all to believe (Acts 17:30), and as if God intends to summon the elect and harden the non-elect by the same preaching of the gospel (2 Corinthians 2:15-16).
In other words, the content and the preaching of the gospel could be and should be
completely consistent with the doctrines of election and reprobation, as well as all other
related doctrines. For many people, to affirm the "sincere offer" is merely an excuse to
believe like a Calvinist, but preach like an Arminian.
It follows that, when preaching the gospel (when we are dealing with the grace that
saves), we should not tell our hearers that God loves all of them, but we should boldly
declare that God loves only the elect and desires (and thus has decreed) their salvation,
and that he hates the reprobates and desires (and thus has decreed) their damnation