Never doubt for a moment how practical—and pointed—the book of Deuteronomy can be.
Are we still living under the Law? No, “for Christ is the end of the law for righteousness to everyone who believes” (Rom 10:4). This doesn’t mean we no longer have commands to obey. The New Testament is full of commands, and Jesus said, “If you love Me, keep My commandments” (Jn 14:15). It is the principle of Law that no longer binds us. The Law included the penalties with the commands, but provided no power to live it. Now Christ’s commands are His enablings. Included in the command is the power to do it! The Lord doesn’t ask us for the strength to obey, just the willingness. Thus God “is able to do exceedingly abundantly above all that we ask or think, according to the power that works in us” (Eph 3:20). But let’s notice the practical application. “Take heed to yourself, and diligently keep yourself, lest you forget the things your eyes have seen, and lest they depart from your heart all the days of your life. And teach them to your children and your grandchildren” (Deut 4:9). Where it all starts? In our own hearts! The Lord Jesus said, “Take heed to yourselves. If your brother sins against you, rebuke him; and if he repents, forgive him” (Lk 17:3). In other words, before thinking about others’ sins, first realize how much you need God’s grace. Paul said to the Ephesian elders, “Take heed to yourselves and to all the flock” (Acts 20:28). You can’t lead others well if you aren’t following Christ yourself. Here Moses says to diligently keep ourselves so we have the moral rigor to lead our children and grandchildren. Paul, John, and Jude give us three practical pointers: “Keep yourself pure” (1 Tim 5:22). “Keep yourselves from idols” (1 Jn 5:21). “Keep yourselves in the love of God” (Jude 21). Holiness. Devotedness. Nearness. Three keys!