The first recorded command of Jesus was not “Go”, but “Repent”. In this respect, he joined the ranks of the great Old Testament prophets for that was their unanimous message to God’s people across all the centuries of their existence. We have seen how some of the most profound missional passages in the Old Testament come in the contexts of the exposure of Israel’s failure and the call for radical repentance.
So it must be for the church. We cannot go forth in mission to the world without attending to ourselves. This is not to suggest that we have to wait until we are perfect before we engage in mission. There never would have been any mission – Old or New Testament – if that had been the case. It means that part of our missional responsibility has to include facing up to the failings and shortcomings of the church itself – precisely because they are such a damning hindrance to God’s mission through us.
From The Mission of Gods People (Biblical Theology for Life) (p. 282)