Blessed Elder Paisios the Athonite 1924-1994
There’s no need for us to tell Christians who aren’t Orthodox that they’re going to hell or that they’re antichrists; but we also mustn’t tell them that they’ll be saved, because that’s giving them false assurance, and we’ll be judged for it. We have to give them a good kind of uneasiness — we have to tell them that they’re in error…In order for us to pray with someone, we must agree on the faith. (Elder Paisios of Mount Athos by Hieromonk Isaac pg. 658)