These are strange words, and they shock, and of course they are meant to shock. Whatever can he mean? Well, it becomes clear what he means.
It may seem confusing on the surface because this was the same Saviour who taught that people must love one another, and this is the same Saviour who, in his law had given mankind all the standards of support and love and affection among families. But there is no contradiction of all that, it's quite obvious coupled with the illustrations he gives. He is establishing the point that to follow him really and truly and sincerely, will mean putting him above all your existing values and relationships in this world.