1 John 4:8 says that the one who does not love does not know God because God is love. This might be legitimately read as: God is love; knowing God therefore necessarily involves knowing love; therefore, the one who does not know love does not know God.

But that’s not precisely what John says. He doesn’t say, “The one who doesn’t know love doesn’t know God.” He says, “The one who doesn’t love doesn’t know God.” The test of knowing God is not “knowing love” but “loving.” It’s an active, pragmatic test, a test that has to do with practice.

The reason we can be sure a non-loving person doesn’t know God is because God is love. There is a circle here: Verse 7 says that the one who loves knows God; verse 8 implies that the one who knows God loves. But this again implies more than epistemology. Knowledge of the God who is Love involves love-in-action. If the love of God manifested in Jesus does not find an echo in our love of one another, we don’t know God.