Oswald Bayer wrote an excellent book, Theology The Lutheran Way. Here is an insightful comment from that book.
What does the passive/receptive life (vita passiva) or the passive righteousness (iustitia passiva) mean, systematically for faith and theology? The righteousness of faith is passive in the sense that “we let God work in us by himself and we with all our powers do nothing of our own.” “Faith, however, is a divine work in us which changes us and makes us to be born again of God, John 1[:12-13]. It kills the old Adam and makes us altogether different, in heart and spirit and mind and powers” (cf. Deut. 6:5). Faith then is entirely God’s work and not a human achievement. We can only “suffer” it. Christian righteousness, which is passive, is entirely opposite to works-righteousness. We can only receive it. We do not work but let another work in us, namely, God. Christian righteousness is not understood by the world. It is hidden from people trapped in themselves and want to boast of their own achievements. It is hidden from those who not only want to make something of themselves but who want to be self-made people.
Oswald Bayer, Theology the Lutheran Way, Lutheran Quarterly Books, edited and translated by Jeffrey G. Silcock and Mark C. Mattes, (Grand Rapids, MI: Eerdmans, 2007 [orig. 1994]), p. 24.