2 so that you, your children and their children after them may fear the LORD your God as long as you live by keeping all his decrees and commands that I give you, and so that you may enjoy long life.

Read Deuteronomy 6:2 Using Other Translations

That thou mightest fear the LORD thy God, to keep all his statutes and his commandments, which I command thee, thou, and thy son, and thy son's son, all the days of thy life; and that thy days may be prolonged.
that you may fear the LORD your God, you and your son and your son's son, by keeping all his statutes and his commandments, which I command you, all the days of your life, and that your days may be long.
and you and your children and grandchildren must fear the LORD your God as long as you live. If you obey all his decrees and commands, you will enjoy a long life.