DEUT1110 "You may not ignore it" [The verse discusses returning a lost object to its owner.] We have been admonished herein not to be lax in helping recover another person's money [or property], whether they are movable possessions or land, as our Sages, z"l, said (Bava Metzia 31a), "You shall do the same for any of your brother's lost articles' [this verse] -- this comes to include the loss of land." For example, if one sees his neighbor's land threatened by flooding, he must elect a barrier against it. We are also exhorted to attempt to rescue our fellowmen and to devise ways to help them in their time of need, as the pasuk states (Vayikra 19:16), "You must not stand by while your fellow man's blood is being shed." Shlomo said (Mishlei 24:10), "If you were faint on the day of trouble, your strength will be constricted." What this means is: if it is within your power to save someone through advice or effort, and you make it seem as if you have no ability or strength [to do so]--your strength will be constricted, measure for measure. Following this the pasuk says (ibid. 12), "Lest you say, 'Indeed, we did not know this!' The One who dwells within the hearts, He understands, and the Guardian of your soul, He knows, and He repays man according to his work." So we see that one who refrains from saving [another] and from devising ways of helping [him], Hashem regard this as [that person's] "work" [I.e. as if he has actively sinned.]