Only God deserves the thanks of man. We speak of true and essential gratitude – of the gratitude in which man must accept permanently and unreservedly the benefit he has experienced as the benefit which he simply cannot do without, as the perfect benefit showered upon him in the sovereign freedom of the Benefactor. We thus speak of a gratitude in which acceptance of the blessing has a depth and abandon and constancy corresponding to its character, in which obligation towards the Benefactor is felt to be absolute so that it cannot be fully discharged by any attitude of gratefulness which it may arouse. There are also other and more modest benefits. All the benefits which one creature can be or give towards another belong to this category. We do not underestimate the fact that these other more modest benefits exist, and that they are genuine benefits because first and last God the Creator is their source. Similar there is also another and more modest type of gratitude – the gratitude which creatures may show one another for reciprocal favour, and which can be genuine because first and last it is to God that they are thankful when thy receive genuine benefits. Butt his also implies that all other thanksgiving is weighed in the scales and placed under the question whether it refers to a genuine benefit of God for which man is giving thanks, and whether it is therefore the true and essential gratitude which is appropriate to this benefit. Our present theme is this true and essential gratitude. The divine benefit demands this. And it alone can do so. It alone is the indispensable, perfect and free blessing poured out upon man. It alone promises the grace which maintains and saves man. It alone spells the salvation which alone can and does help the creature living on the edge of the abyss of destruction. Hence it alone merits thanks in the strictest sense of the term. Because God alone can be and is a Benefactor in this sense, the One in relation to whom man can and will transcend the limits of his intrinsic possibilities (which is what happens when he thanks God), therefore God alone deserves thanks. Thanksgiving is wasted, indeed, it rests on error and can only lead to further error, if it is not directed tot he one benefit of this one Benefactor, even in the grateful acceptance of benefits from creaturely benefactors. As thanksgiving which is part of an absolute obligation and is permanently binding, it can be directed to this one benefit alone and therefore to this one Benefactor alone.
Church Dogmatics III/2, 169