Genesis 18:19

19.For I know him, that he will command his children. The second reason why God chooses to make Abraham a partaker of his counsel is, because he foresees that this would not be done in vain, and without profit. And the simple meaning of the passage is, that Abraham is admitted to the counsel of God, because he would faithfully fulfill the office of a good householder, in instructing his own family. Hence we infer, that Abraham was informed of the destruction of Sodom, not for his own sake alone, but for the benefit of his race. Which is carefully to be observed; for this sentence is to the same effect, as if God, in the person of Abraham, addressed all his posterity. And truly, God does not make known his will to us, that the knowledge of it may perish with us; but that we may be his witnesses to posterity and that they may deliver the knowledge received through us, from hand to hand, (as we say,) to their descendants. Wherefore, it is the duty of parents to apply themselves diligently to the work of communicating what they have learned from the Lord to their children. In this manner the truth of God is to be propagated by us, so that no one may retain his knowledge for his own private use; but that each may edify others, according to his own calling, and to the measure of his faith. There is however no doubt, that the gross ignorance which reigns in the world, is the just punishment of men’s idleness. For whereas the greater part close their eyes to the offered light of heavenly doctrine; yet there are those who stifle it, by not taking care to transmit it to their children. The Lord therefore righteously takes away the precious treasure of his word, to punish the world for its sloth. The expression after him is also to be noticed; by which we are taught that we must not only take care of our families, to govern them duly, while we live; but that we must give diligence, in order that the truth of God, which is eternal, may live and flourish after our death; and that thus, when we are dead, a holy course of living may survive and remain. Moreover, we hence infer, that those narratives which serve to inspire terror, are useful to be known. For our carnal security requires sharp stimulants whereby we may be urged to the fear of God. And lest any one should suppose that this kind of doctrine belongs only to strangers, the Lord specially appoints it for the sons of Abraham, that is, for the household of the Church. For those interpreters are infatuated and perverse, who contend that faith is overturned if consciences are alarmed. For whereas nothing is more contrary to faith than contempt and torpor; that doctrine best accords with the preaching of grace, which so subdues men to the fear of God, that they, being afflicted and famishing, may hasten unto Christ.

And they shall keep the way of the Lord. Moses intimates, in these words, that the judgment of God is proposed, not only in order that they who, by negligence, please themselves in their vices, may be taught to fear, and that being thus constrained, they may sigh for the grace of Christ; but also to the end that the faithful themselves, who are already endued with the fear of God, may advance more and more in the pursuit of piety. For he wills that the destruction of Sodom should be recorded, both that the wicked may be drawn to God, by the fear of the same vengeance, and that they who have already begun to worship God, may be better formed to true obedience. Thus the Law avails, not only for the beginning of repentance, but also for our continual progress. When Moses adds, to do justice and judgment, he briefly shows the nature of the way of the Lord, which he had before mentioned. This, however, is not a complete definition; but from the duties of the Second Table, he briefly shows, by the figure synecdoche, what God chiefly requires of us. And it is not unusual in Scripture, to seek a description of a pious and holy life, from the Second Table of the Law; not because charity is of more account than the worship of God, but because they who live uprightly and innocently with their neighbors, give evidence of their piety towards God. In the names of justice and judgment he comprehends that equity, by which to every one is given what is his own. If we would make a distinction, justice is the name given to the rectitude and humanity which we cultivate with our brethren, when we endeavor to do good to all, and when we abstain from all wrong, fraud, and violence. But judgment is to stretch forth the hand to the miserable and the oppressed, to vindicate righteous causes, and to guard the weak from being unjustly injured. These are the lawful exercises in which the Lord commands his people to be employed.

That the Lord may bring upon Abraham that which he hath spoken of him. Moses intimates that Abraham should become possessed of the grace promised to him, if he instructed his children in the fear of the Lord, and governed his household well. But under the person of one man, a rule common to all the pious is delivered: for they who are negligent in this part of their duty, cast off or suppress, as much as in them lies, the grace of God. Therefore, that the perpetual possession of the gifts of God may remain to us, and survive to posterity, we must beware lest they be lost through our neglect. Yet it would be false for any one hence to infer, that the faithful could either cause or deserve, by their own diligence, that God should fulfill those things which he has promised. For it is an accustomed method of speaking in Scripture, to denote by the word that the consequence rather than the cause. For although the grace of God alone begins and completes our salvation; yet, since by obeying the call of God, we fulfill our course, we are said, also in this manner, to obtain the salvation promised by God.