Teach them - The Hebrew word is emphatic, and signifies "enlightenment." The text gives four distinct points:
(a) the "ordinances," or specific enactments,
(b) "the laws," or general regulations,
(c) "the way," the general course of duty,
(d) "the works," each specific act.

Thou shalt teach them ordinances - חקים chukkim, all such precepts as relate to the ceremonies of religion and political economy. And laws, התורת hattoroth, the instructions relative to the whole system of morality.
And shalt show them the way - אה הדרך eth hadderech, That very Way, that only way, which God himself has revealed, and in which they should walk in order to please him, and get their souls everlastingly saved.
And the work that they must do - For it was not sufficient that they should know their duty both to God and man, but they must Do it too; יעשון yaasun, they must do it diligently, fervently, effectually; for the paragogic nun deepens and extends the meaning of the verb.
What a very comprehensive form of a preacher's duty does this verse exhibit! 1. He must instruct the people in the nature, use, and importance of the ordinances of religion. 2. He must lay before them the whole moral law, and their obligations to fulfill all its precepts. 3. He must point out to each his particular duty, and what is expected of him in his situation, connections, etc. And, 4. He must set them all their work, and see that they do it. On such a plan as this he will have full opportunity to show the people, 1. Their sin, ignorance, and folly; 2. The pure and holy law which they have broken, and by which they are condemned; 3. The grace of God that bringeth salvation, by which they are to be justified and finally saved; and, 4. The necessity of showing their faith by their works; not only denying ungodliness and worldly lusts, but living soberly, righteously, and godly in this present world, looking for that blessed hope, and the glorious appearing of the great God and our Savior, Jesus Christ.

And thou shalt teach them ordinances and laws,.... Both with respect to things civil and religious, which he should receive from God:
and shalt show them the way wherein they must walk; the path of faith and duty, the way of truth, holiness, and righteousness:
and the work that they must do; both with respect to God, and one another, the various duties and exercises of religion, everything relating to their moral, religious, and civil conduct.