But we must learn by all means that forgiveness of sins, Christ, and the Holy Spirit are granted – and granted freely – only when we hear with faith. Even our huge sins and demerits do not stand in the way. We must not consider how great the thing is that is being given and how unworthy we are; otherwise the greatness both of the thing and of our unworthiness will frighten us away. But we must be
ar in mind that it pleases God to grant this inexpressible gift to us freely – to us who are unworthy. As Christ says in Luke 12:32: you [give, He says] the kingdom.” To whom? To you unworthy ones, who are His little flock. Therefore if I am little and the thing that is being given to me is great – in fact, the greatest there is – I must think that the One who is giving it to me is also great and that He alone is great. If He is offering it and wants to give it, I do not consider my own sin and unworthiness. No, I consider the fatherly will that he who is giving it has toward me. I accept the greatness of the gift with joy; and I am happy and grateful for such an inestimable gift granted to me in my unworthiness, freely and by hearing with faith.
Luther’s Works, volume 26, (214)