Powtórzonego Prawa 15:11 Komentarz: Rashi, Chizkuni, Ramban & Ibn Ezra

על כן means מפני כן BECAUSE OF THIS.

כי לא יחדל אביון, “for there will not cease to be destitute people.” This sounds like a contradiction to what the Torah had promised in verse 4, where it stated that there would not be destitute people in our land. The promise in verse 4 had been linked to a condition. i.e. that the entire population observes the sh’mittah and yovel legislation. The critical word there had been the word כי. In our verse here this word occurs again but here it means: “maybe, possibly.” In our paragraph the word כי occurs no fewer than four times. It has a different meaning each time. We have a conditional word כי in כי יהיה בך אביון, “if there should be among you a destitute person;” we have a word כי meaning “but,” in כי פתוח תפתח, “but you shall definitively open your hand;” we have the word כי meaning “because of” in בגלל הדבר הזה, “for the sake of this matter G-d will bless you;” and we have the word כי meaning “so that not,” in כי לא יחדל אביון “if perchance your actions were not charitable enough to prevent the existence of destitute people among you.”

FOR THE POOR SHALL NEVER CEASE OUT OF THE LAND. Commentators³⁰²Reference is to Ibn Ezra and others. have said that the meaning thereof is that the poor shall never cease out of the Land at any of all times, for there will always be poor in the Land, for it was apparent before Him that they will not do [to make possible] what he said to them, But there shall be no needy among you,³⁰³Above, Verse 4. if only thou diligently hearken unto the voice of the Eternal thy G-d to observe to do all this commandment.³⁰⁴Verse 5. But it is not correct in my opinion, for the Torah may allude to what will be but it would not explicitly prophesy about them [the Israelites] that they will not fulfill the Torah, nor would he have commanded them [to observe the commandments while foretelling] that they would always transgress them. Forbid it! It is only by way of warning that he mentions [their transgressions].
The correct interpretation is that he says that it is impossible for the poor to cease so that none should ever exist. He [Moses] mentioned this because, having assured them that there would be no needy if they observe all the commandments³⁰⁵Verse 7. he said: “But I know that not all generations forever will observe all the commandments in which case there would be no need to charge you concerning the poor, for perhaps, at some time, there will exist poor and so I command you about him if he will be found.” He states out of the Land [for the poor shall never cease ‘out of the Land’] in order to allude to the entire habitation [anywhere on earth], for the promise that there would not be needy among us applies in the Land which the Eternal our G-d giveth us for an inheritance³⁰³Above, Verse 4. if we will fulfill there all the commandments. And now he said that it is possible that, at some period or at some place where you will have settled, there be found a poor man among you. For the meaning of the expression in thy Land³⁰⁵Verse 7. [If there be among you a needy man … ‘in thy Land’] is like in all your habitations³⁰⁶Exodus 12:20. — within the Land of Israel and outside of the Land.

לאמר suggests: I give you good advice for your own benefit (Sifrei Devarim 118:2).