Commento su Genesi 18:19

כי ידעתיו FOR I KNOW HIM — this is an expression denoting "affection", as (Ruth 2:1) "kinsman (מודע) of her husband," and (Ruth 3:2) “And is not Boaz our kinsman (מודעתנו), and (Exodus 30:17) “I have distinguished (ידעתיך) thee by name”. Still the primary meaning of these terms connected with the root ידע is really that of knowing, for whoever holds a person in affection attaches him to himself, so that he knows him well and is familiar with him. And why do I hold him dear?

FOR I HAVE KNOWN HIM (‘YEDATIV’), TO THE END (‘LEMA’AN’) THAT HE MAY COMMAND HIS CHILDREN. Rashi comments: “For I have known him, as the Targum takes it, is an expression denoting affection, just as A kinsman (‘moda’) of her husband’s;¹²⁰Ruth 2:1. And I know thee.¹²¹Exodus 33:17. Still the main connotation of all these expressions is that of knowing, for he who holds a person in affection and draws him to himself knows him well and is familiar with him. But if you explain it as the Targum does — i.e., “I know that he will command his children” — then the word lema’an (to the end) does not fit into the sense.”¹²²Our Rashi has a different text. See notes in my Hebrew commentary, p. 110. See also Note 125 further.
It is possible that the word yedativ means “I have raised him and elevated him so that he shall command his children after him to do that which is right before Me, and therefore I will make him a great and mighty nation so that he should serve Me. In a similar sense are the verses: I know thee (‘yedaticha’) by name;¹²³Exodus 33:12. The sense would thus be: “I have made thee great in name.” What is man, that Thou knowest htm?¹²⁴Psalms 144:3. The sense here then would be: “What is man before Thee that Thou hast given him greatness?” Or the verse may be stating, I know that he will command,¹²⁵Ramban thus differs with Rashi, who said that if you take the sense of the verse to be, “I know of him that he will command,” then the word lema’an does not fit the context. Ramban proceeds to show from Exodus 23:12 that the words lema’an yanuach mean she’yanuach (that he may rest); here likewise, lema’an asher yetzaveh means she’yetzaveh (that he will command). Thus, the word lema’an is seen to fit into the context. and in a similar sense is the verse, So that thine ox and thine ass may have rest (lema’an yanuach),¹²⁶Exodus 23:12. See Note above. meaning that he may have rest.
The correct interpretation appears to me to be that the word yedativ literally means “knowing.” He is thus alluding that G-d’s knowledge, which is synonymous with His Providence in the lower world, is to guard the species, and even the children of men are subject despite it to the circumstantial evil occurrences until the time of their visitation comes. But as regards His pious, He directs His Providence to know each one individually so that His watch constantly attaches to him, His knowledge and remembrance of him never departs, as it says: He withdraweth not His eyes from the righteous.¹²⁷Job 36:7. There are many verses on this theme, as it is written, Behold, the eye of the Eternal is toward them that fear Him,¹²⁸Psalms 33:18. See Moreh Nebuchim III, 51, where Rambam’s theory on Divine Providence is seen to be similar to that which Ramban expresses here. and other verses besides.

כי ידעתיו, as a symbol of righteousness.