This statement appears to be a safeguard against those who pretend to love the brothers through mere outward activity, yet are not genuine in their hearts and have other agendas. John therefore says that a true test of one’s love for the children of God is whether he loves God and obeys God’s commands.1
2 Nous connaissons que nous aimons les enfants de Dieu, lorsque nous aimons Dieu, et que nous pratiquons ses commandements.