and with all deception of wickedness for those who are being lost, because they didn't receive the love of the truth, that they might be saved.
To reject the truth (gospel) is to reject Christianity, as Peter says, "Wherefore I will not be negligent to put you always in remembrance of these things, though ye know them, and be established in the present truth" (2 Peter 1:12). The entire message of this verse is that truth leads to salvation while unrighteousness leads to perishing.