Thomas Aquinas

Second, by the great things which he does in others. And first, in those whom he strengthens, he shows their original weakness: it is he that gives strength, as to him who first had been strong and then weakened; to them that are not, as to those who were not strong, above: you have been a strength to the poor (Isa 25:4); he calls those things that are not (Rom 4:17); the weak things of the world has God chosen (1 Cor 1:27).

Commentary on Isaiah ↗