From the Word
35 But love your enemies, and do good, and lend, expecting nothing in return; and your reward will be great, and you will be sons of the Most High; for he is kind to the ungrateful and the selfish. 36 Be merciful, even as your Father is merciful.
Luke 6:35–36, RSV
How is God our heavenly Father merciful? In this that he gives us all things, natural and spiritual, temporal and eternal, gratuitously and out of pure goodness. For should he give unto us according to our merits, he would have to give us only eternal condemnation. Therefore what he gives us in our possessions and honor is given out of pure mercy. He sees that we are captives of death; he is merciful and gives us life. He sees that we are the children of hell; but he is merciful and gives us heaven. He sees that we are poor, naked and exposed, hungry and thirsty; but he is merciful and clothes, feeds and gives us drink, and satisfies us with all good things. Thus, whatever we have, for the body or spirit, he gives us out of mercy, and pours his blessings over us and into us. Therefore Christ says: Imitate your Father and be also merciful as he is merciful.
This is not a common mercy, nor one that reason teaches. For that is selfish; it gives to the great and learned; it loves those who are beautiful; it gives to those from whom it has some benefit or advantage. It is a politic, beggarly, piece-meal mercy. Christians must not seek their own, but look at all alike, whether friend or foe, as our heavenly Father does. Where this mercy is not, there is also no true faith. For if your heart is not in the state of faith so that you know your God has revealed himself to you as good and merciful, without any merit on your part, while you were still an enemy and a child of wrath; if you believe this, you cannot refrain from showing yourself in like manner to your neighbor, and do all, out of the love of God, for your neighbor’s welfare. Therefore see to it that you make no distinction between friend and foe, the worthy and the unworthy. This has been said of faith and works, namely, that the motion of faith is inwards and upwards, of works, outward and downward. For thus we are righteous before God and men, in that we honor God and look direct to him and believe according to his Word, and in love do what we can for our neighbor.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 296–97.