Genesis 18:19 For I know him, that he will command his children and his household after him, and they shall keep the way of the Lord, to do justice and judgment; that the Lord may bring upon Abraham that which he hath spoken of him.
The Lord knows Abraham. He knows what his responses to His Gracious Covenant Promises would be. God’s foreknowledge knows this, but it did not make it happen. God did not choose Abraham because he knew ahead of time how he would respond. God chose Abraham to be the one who would bring God’s Salvation and His Savior into the world to bless all people out of sheer grace. God did not choose him because he knew he would respond in faith and obedience. Abraham responded in faith because God chose him by grace. Grace is always first, and then faith.
Here the Lord is referring to this response: he will command his children and his household after him. Abraham’s faithful response was to teach His family and succeeding generations the way of the Lord so that they would keep (believe) it. The ”way of the Lord” is grace and love; God is faithful to keep His covenant promises. Thank God Abraham taught his son and grandson, or the promise would have been stopped.
We also respond to God’s promise of salvation by “commanding our children.” The head of the household teaches the faith to the family by word and deed, teaching and example. He or she takes charge of their training and education. The fathers and mothers pray for their children and grandchildren and all generations to come. We pray that they will come to and remain in the faith that was ”once delivered to the saints.” Children who have been ”trained up in the way they should go” will keep the way of the Lord. ”The Way” is Jesus.