Albert Barnes Commentary Psalms 146:9

"Jehovah preserveth the sojourners; He upholdeth the fatherless and widow; But the way of the wicked he turneth upside down." — Psalms 146:9 (ASV)

The Lord preserves the strangers—He regards them with interest; He defends and guides them. This is the ninth reason why those who trust in the Lord are happy.

The stranger—away from home and friends, with no one to feel an interest in him or sympathy for him, with the feeling that he is forsaken, with no one on whom he can call for sympathy in distress—may find in God one who will regard his condition, who will sympathize with him, and who is able to protect and befriend him. Compare Exodus 12:49; Exodus 22:21; Exodus 23:9; Leviticus 19:33; Deuteronomy 1:16; Deuteronomy 10:18–19; Isaiah 56:3, Isaiah 56:6.

He relieves the fatherless and widow—He is their friend. This is the tenth reason why those who put their trust in the Lord are happy. It is that God is the Friend of those who have no earthly protector. See the notes at Psalm 68:5: A father of the fatherless, and a judge of the widows, is God in his holy habitation.

But the way of the wicked He turns upside down—He overturns their plans, defeats their schemes, and makes their purposes accomplish what they did not intend. The Hebrew word here means to bend, to curve, to make crooked, to distort; then, to overturn, to turn upside down.

The same word is applied to the conduct of the wicked in Psalm 119:78: They dealt perversely with me. The idea here is that their path is not a straight path; that God makes it a crooked way; that they are diverted from their design; that through them He accomplishes purposes which they did not intend to accomplish; that He prevents them from accomplishing their own designs; and that He will make their plans subservient to a higher and better purpose than their own.

This is the eleventh reason why those who put their trust in God are happy. It is that God is worthy of confidence and love, because He has all the plans of wicked men entirely under His control.