"Teach me your way, O Lord, and lead me in a plain path." (Psalm 27:11) "Blessed is the man ... [Whose] delight is in the law of the Lord, and who meditates therein day and night [that he may know the way of God]. ... For the Lord knows the way of the righteous." (Psalm 1:1-2,6)
The "Lord knows the way" of such a one; that is, the Lord knows the way of those who know His way. When one, through constant meditation therein, knows the way of God, and has learned the secret of the Lord, his own way is assured; God knows exactly what course he will take, and can trust him in any circumstances.
Abraham knew God's way, and therefore God could say of him, "I know him, that he will command his household after him, and they shall keep the way of the Lord." (Genesis 18:19)
God knew Abraham's way, because Abraham knew His way. Our way is regulated entirely by our knowledge of God's way. It was because "[God] made known His ways unto Moses," (Psalm 103:7) that He could say of him, "I know you." (Exodus 33:17)--Present Truth, January 15, 1903--Original title: Back Page--Psalm 27:11.