Whenever we are not yet born in Holy Spirit (John 3:5) with a heavenly birth but are only born as natural men by natural birth, we are confined to a limited love of our kin, who are everything to us. It is good for the time being, even divine, for it is from God that we have in our hearts intense love towards parents, siblings, sons and daughters, dear relatives or romantic lovers. However, this can become our obstacle also, for "man's enemy will be members of his household" (Matthew 10:36).
But how that, which is divine can become an enemy? Because the family members can block our birth and progress in Spirit. For instance, you have a romantic infatuation with a woman whose beauty is like that of Hellen of Troy, and whose embrace feels like a paradise; but you then come to a knowledge that she is not a Christian, neither wants to be a one, and does not see life as a service of God and growth in Christ, as you do, but just a dolce vita of earthly pleasures and comforts. It is a temptation that you sell out the Lord for the romantic infatuation and thus exchange eternal for the temporal; Or, you love your child so much and so wrongly, that you mercilessly sink businesses of other men depriving their children of sustenance; or your father is a politician and asks you to abandon expressing your Christian views on, say abortion or homosexuality, for it can harm his electoral campaign, and you pusillanimously comply; etc. In short, our closest persons whom we love the most can become the greatest temptations for us that we may betray the Lord for their sake.
However, if we overcome this temptation, are born in the Lord's Spirit, enter through the fire of the Spirit burning in us in a good and noble conflict even with our kin, just as the Lord wishes this fire of Spirit to be kindled in us (Luke 12:49) and even urges through His apostle not to quench it in our hearts and lives (1 Thes. 5:19), then we shall become friends of all those who love the Lord and kin to them with the kinship of Spirit.
But, eventually, we shall not lose even our natural kins, our natural parents, or siblings, or even romantic love, for if we die for sin and are born in Spirit, the Lord will grant us souls of even our kins, whom we shall continue loving albeit in a more sublime, spiritual way. As Paul, being born in Spirit, and through it having become friend of all nations, for Spirit has not preference for particular nations, prays for his kin Jews most ardently, and is confident that his prayers will help Jewish nation eschatologically (cf. Romans 11:26). Thus, we shall obtain entire world of Lord's followers, and be persecuted by lovers of the world for that reason ( for loving of this world is hatred towards God (1 John 2:15)), among them by our family members even, but through our endurance and care for them in Christ, we have a chance to re-obtain them in Him.