For I know him, that—literally, for I have known (or chosen, יָדַע being—dilexi, as in Amos 3:2) him to the end that, the language expressing the idea that Abraham had been the object of Divine foreknowledge and election (Gesenius, Rosenmüller, Delitzsch, Keil, Oehler, Kalisch, Lange), although the reading of the text is substantially adopted by many (LXX; Vulgate, Targums, Luther, Calvin, Dathe, et alii).
The latter interpretation assigns as the reason of the Divine communication the knowledge which Jehovah then possessed of Abraham's piety; the former grounds the Divine resolution on the prior fact that Divine grace had elected him to the high destiny described in the language following.
It is generally agreed that this clause connects with Genesis 18:17; Bush regards it as exhibiting the means by which the future promised to Abraham in Genesis 18:18 should be realized—he will command his children and his household after him (by parental authority as well as by personal example), and they shall keep the way of the Lord,—i.
e. the religion of Jehovah (cf. 2:22; 2 Kings 21:22; Psalms 119:1; Acts 18:25), of which the practical outcome is—to do justice and judgment;—or righteousness and judgment, that which accords with right or the sense of oughtness in intelligent and moral beings, and that which harmonizes with the Divine law (cf.
Ezekiel 18:5)—that (literally, to the end that, in order that, לְמַעַן, ut supra) the Lord may bring upon Abraham that which he hath spoken of him.