Just before this Gospel passage Jesus has imposed a huge burden of responsibility on his disciples: the warning that becoming the cause of others’ stumbling would bring on a fate worse than being cast into the sea attached to a millstone (a cement overcoat, perhaps, these days); and a demand to exercise a capacity to forgive that knows no limits and gives all benefit of the doubt to the offender. Faced with this challenge the apostles, reasonably enough, doubt their own competence and call for help “Lord, increase our faith”. So too should we, to whom the extreme challenge of this teaching is also directed.
Jesus, typically, shifts them (and ourselves) on to new ground in his reply, saying in effect that what is needed is the exercise of faith, rather than its increase. Even the smallest possible faith should allow us to follow the Jesus’ teaching, to achieve what is humanly impossible, for faith is the gift of God and the power of God working in and through us. The graphic imagery of the tree being uprooted and replanted in the sea echoes one of the antitheses in the Lord’s commissioning of Jeremiah as a prophet: he is to “pluck up … and to plant” (Jer 1:10). Grafted on to this is a glimpse of creation made new – the tree flourishing not in salt chaos but in the life-giving spring of the Spirit. We too have been commissioned as prophets (and priests and kings) by the power of the Spirit given to us in our baptisms. Faith here means an awareness of the presence of the kingdom of God in the ministry of Jesus. Through faith the apostles (and, by extension, ourselves) participate in God’s saving work in and through Jesus. However meagre and unformed our faith its active exercise allows us to cooperate with God in establishing his kingdom.
Aquinas, following Augustine, played around with three senses of what we might mean when we say we believe in God: believing God to be God, that is recognising the living God as the object of our faith and rejecting our false idols and securities; believing God, believing God’s self-revelation in his Word, in Jesus and in the scriptures; believing in God, believing God to be the Holy Mystery into which our hearts are, to their healing, being drawn. Believing in God then requires that we believe in nothing else; that our faith in God articulates a stance to the world that is exclusive of the dominant idolatries of our culture, especially its worship of power and success. Our faith, our belief in God opens us up, inescapably, to the demands of justice, peace and the integrity of all God’s creation being made anew.
These demands are powerfully articulated in Habbakuk’s complaint, and God reassures him that the kingdom will come, if seemingly slowly to us, because God will effect its fulfilment, and this cannot be obstructed by anything creatures can do. Of course, if we do not fan into flames the gift of the Spirit given to us we can hinder only our own entry into the kingdom, into the joy of those blessed the vision of God’s presence. Exercising or realising our faith, allowing it to enliven us means allowing the Spirit’s gifts of power, love and self-control to bear their fruit in and though our service to others. James has summed it up in his Epistle “I by my works will show you my faith … [and] faith if it has no works, is dead in itself”. Belief, if real, spills over into action.