But anyone who does not love does not know God, for God is love.
1 John 4:8 NLT
I think we try to over complicate the Gospel sometimes. Like the Pharisees, we place the focus on appearance and rule keeping. When asked which commandment was most important Jesus kept it
simple: Love God with all your heart, all your soul, and all your mind, and love your neighbor as yourself. It's all about love. That's what Paul was saying when he exhorted us to live as citizens of heaven.
Above all, you must live as citizens of heaven, conducting yourselves in a manner worthy of the Good News about Christ. Then, whether I come and see you again or only hear about you, I will know that you are standing together with one spirit and one purpose, fighting together for the faith, which is the Good News. Philippians 1:27
When we lay aside our petty differences, stand together with one spirit, and love as Jesus loved, then we are living worthy of the Good News.
They will know we are His disciples by our love . . .