Now that you have purified yourselves by obeying the truth so that you have sincere love for your brothers, love one another deeply, from the heart.Notice the deep connection between purifying yourself and loving others.
Have you ever met someone who claimed to be a Christian, yet used such words of hatred when it came to homosexuals? Or maybe you (like me) came from some tiny little town and a tiny little church, and you could tell that the elders in the church looked down with great disdain on the black families that were moving into the neighborhoods around the church. It could have been as simple as the way people in your church talked about that other church that was "way too liberal" in their music and such.
Did you ever feel like there was something wrong with that? That it just seemed off? Well, you were right to feel that way. In this verse, like so many others, there is an absolute connection between loving God and loving others. It is inescapable.
The real question to ask though is, how do you stand? Are you loving your neighbors. It is always so much easier to see the lack of love in others, but have you been examining yourself?