Adam Clarke on Psalms 41:1

Blessed is he that considereth - God is merciful; he will have man to resemble him: as far as he is merciful, feels a compassionate heart, and uses a benevolent hand, he resembles his Maker; and the mercy he shows to others God will show to him. But it is not a sudden impression at the sight of a person in distress, which obliges a man to give something for the relief of the sufferer, that constitutes the merciful character. It is he who considers the poor; who endeavors to find them out; who looks into their circumstances; who is in the habit of doing so; and actually, according to his power and means, goes about to do good; that is the merciful man, of whom God speaks with such high approbation, and to whom he promises a rich reward.