Matthew 18:11

"For the Son of Man is come to save that which was lost." Again, He is putting another reason stronger than the former, and connects with it a parable, by which He brings in the Father also as desiring these things. ... And by the angels again that are entrusted with these same mean brethren, He makes them objects of veneration, and from His own will and passion (for when He said, "The Son of Man is come to save that which was lost," He signifies even the cross, like as Paul saith, speaking of a brother, "For whom Christ died"); and from the Father, for that neither to Him doth it seem good that one should perish... Him let us also imitate, refusing none of the tasks that seem lowly and troublesome for our brethren's sake; but though we have to do service, though he be small, though he be mean for whom this is done, though the work be laborious, though we must pass over mountains and precipices, let all things be held endurable for the salvation of our brother. For a soul is an object of such earnest care to God, that "He spared not His own Son."

By that which was lost, understand the human race; for all the elements have kept their place, but man was lost, because he has broken his ordained place.

The Lord had said, under the type of hand, foot, and eye, that all kin and connection which could afford scandal must be cut off. The harshness of this declaration He accordingly tempers with the following precept, saying, Take heed that ye despise not one of these little ones; i. e. As far as you may avoid despising them, but next to your own salvation seek also to heal them. But if ye see that they hold to their sins, it is better that ye be saved, than that ye perish in much company. High dignity of souls, that each from its birth has an Angel set in charge over it!