Good and upright is Jehovah. Pausing for a little as it were in the prosecution of his prayer, he exercises his thoughts in meditation upon the goodness of God, that he may return with renewed ardor to prayer. The faithful feel that their hearts soon languish in prayer, unless they are constantly stirring themselves up to it by new incitements; so rare and difficult a thing is it to persevere steadfastly and unweariedly in this duty. And, indeed, as one must frequently lay on fuel in order to preserve a fire, so the exercise of prayer requires the aid of such helps, that it may not languish, and at length be entirely extinguished. David, therefore, desirous to encourage himself to perseverance, speaks to himself, and affirms that God is good and upright, that, gathering new strength by meditating on this truth, he may return with the more alacrity to prayer. But we must observe this consequence -- that as God is good and upright, he stretches forth his hand to sinners to bring them back again into the way. To attribute to God an uprightness which he may exercise only towards the worthy and the meritorious, is a cold view of his character, and of little advantage to sinners, and yet the world commonly apprehends that God is good in no other sense. How comes it to pass that scarcely one in a hundred applies to himself the mercy of God, if it is not because men limit it to those who are worthy of it? No on the contrary, it is here said, that God gives a proof of his uprightness when he shows to transgressors the way; and this is of the same import as to call them to repentance, and to teach them to live uprightly. And, indeed, if the goodness of God did not penetrate even to hell, no man would ever become a partaker of it. Let the Papists then boast as they please of their imaginary preparations, but let us regard this as a sure and certain doctrine, that if God do not prevent men by his grace, they shall all utterly perish. David, therefore, here commends this preventing grace, as it is called, which is manifested either when God in calling us at first renews, by the Spirit of regeneration, our corrupt nature, or when he brings us back again into the right way, after we have gone astray from him by our sins. For since even those whom God receives for his disciples are here called sinners, it follows that he renews them by his Holy Spirit that they may become docile and obedient.

Good and upright is the Lord - His character is benevolent, and he is worthy of confidence. He is not merely "good," but he is equal and just in his dealings with people. This latter attribute is no less a reason for confidence in his character than the former. We need a God who is not merely benevolent and kind, but who is just and faithful; whose administration is based on principles of truth and justice, and in whose dealings, therefore, his creatures can repose unlimited confidence.
Therefore will he teach sinners - Because he is good and upright, we may approach him with the assurance that he will guide us aright. His "goodness" may be relied on as furnishing evidence that he will be "disposed" to do this; his "uprightness" as furnishing the assurance that the path in which he will lead us will be the best path. We could not rely on mere benevolence, for it might lack wisdom and firmness, or might lack power to execute its own purposes; we can rely upon it when it is connected with a character that is infinitely upright, and an arm that is infinitely mighty.
In the way - In the right way - the way in which they should go, the path of truth, of happiness, of salvation.

Good and upright is the Lord - He is good in his nature, and righteous in his conduct.
Therefore will he teach sinners - Because he is good, he will teach sinners, though they deserve nothing but destruction: and because he is right, he will teach them the true way.

Good and upright [is] the LORD: therefore will he (f) teach sinners in the way.
(f) That is, call them to repentance.

Good and upright is the Lord,.... He is essentially, originally, and independently good of himself in his own nature, and he is providentially good to all his creatures; and he is in a way of special grace and mercy good to his own people: and he is "upright", just in himself, righteous in all his ways and works, and faithful in all his promises; and the consideration of these excellent perfections of his encouraged the psalmist to entertain an holy confidence, that his petitions, respecting instruction and guidance in the ways of the Lord, Psalm 25:4; would be heard and answered, notwithstanding his sins and transgressions;
therefore will he teach sinners in the way; such who are in sinful ways, he will teach them by his word and Spirit the evil of their ways, and bring them out of them, and to repentance for them; and he will teach them his own ways, both the ways and methods of his grace, in saving sinners by Christ, and the paths of faith and duty in which he would have them walk; see Psalm 51:13.

We are all sinners; and Christ came into the world to save sinners, to teach sinners, to call sinners to repentance. We value a promise by the character of him that makes it; we therefore depend upon God's promises. All the paths of the Lord, that is, all his promises and all his providences, are mercy and truth. In all God's dealings his people may see his mercy displayed, and his word fulfilled, whatever afflictions they are now exercised with. All the paths of the Lord are mercy and truth; and so it will appear when they come to their journey's end. Those that are humble, that distrust themselves, and desire to be taught and to follow Divine guidance, these he will guide in judgment, that is, by the rule of the written word, to find rest for their souls in the Saviour. Even when the body is sick, and in pain, the soul may be at ease in God.

upright--acting according to His promise.
sinners--the general term, limited by the
meek--who are penitent.
the way--and his way--God's way of providence.

The בּ with הורה denotes the way, i.e., the right way (Job 31:7), as the sphere and subject of the instruction, as in Psalm 32:8, Proverbs 4:11; Job 27:11. God condescends to sinners in order to teach them the way that leads to life, for He is טוב־וישׂר; well-doing is His delight, and, if His anger be not provoked (Psalm 18:27), He has only the sincerest good intention in what He does.

Upright - Holy and true, in all his declarations and offers of mercy to sinners. Therefore - He will not be wanting to such poor sinners as I am, but will guide them into the way of life and peace.