Paul appears to the human experience of being enslaved to sin as a means of showing its futility. The acknowledgement that this kind of life leads nowhere but to death leaves open the possibility of accepting a new kind of life which is freed from the slavery of sin putting oneself at the service of love and justice, therefore commiting one's whole being to authentic living.
In the Gospel passage, Jesus explains further what this commitment will mean. It is far from being a cosy comfortable feeling, sheltered from conflict and division. He is only too aware that commitment to His values will inevitably bring about division and pain right in the midst of the closest of relationships.
The Christian who faithfully bears witness to Christ will undergo the inescapable 'fire' (Lk.12:49) of purification of his faith when he experiences misunderstandings and hostilities, no matter how gentle and tactful he may be. And in some periods and crises he will face actual persecution.
Lord, help me to be totally committed to You and my fellow sisters and brothers, without counting the cost.