The interpretation timeline
Psalm 145:9 Douay-Rheims

The Lord keepeth the strangers, he will support the fatherless and the widow: and the ways of sinners he will destroy.

A.D. 407 – 1849 8 witnesses

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“For as long as your blessed husband was with you, you enjoyed honor and care and zealous attention. In fact you enjoyed such as you might expect to enjoy from a husband; but, since God took him to himself, [God] has taken his place with you. And this is not my saying but that of the blessed prophet David, for he says, "He will take up the fatherless and the widow," and elsewhere he calls him "father of the fatherless and judge of the widow." Thus in many passages you will see that he is earnestly concerned about the cause of this class of people.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“Just as you have; "the Lord, guards proselytes" [Psalm 146:9]. "Proselytes" are strangers. Every Church of the Gentiles is a stranger. For it comes in to the Fathers, not sprung of their flesh, but their daughter by imitating them. Yet the Lord, not any man, guards them. "The orphan and widow He will take up." Let none think that He takes up the orphan for his inheritance, or the widow for any business of hers. True, God does help them; and in all the duties of the human race, he does a good work, who takes care of an orphan, who abandons not a widow: but in a certain way we are all orphans, not because our Father is dead, but because He is absent.”
Source
435
A.D.
John Cassian Patristic
c. A.D. 360–435
“For it is not free will but the Lord who "looses those who are bound." It is not our strength, but the Lord who "raises those who have fallen." It is not our diligence in reading, but "the Lord who enlightens the blind" where the Greek says kyrios sophoi typhlous, that is, "the Lord makes wise the blind." It is not our care, but "the Lord who cares for the stranger." It is not our courage, but "the Lord who assists (or supports) all those who are down."”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“strengthens Heb. יעודד, an expression of strength.”
1167
A.D.
Ibn Ezra Jewish
1089–1167
“"God guards converts" - Who have no aid as they are from another nation. And the word "יעודד" - I have explained it [already]. And the meaning of "He will twist" is that he will switch causes. He will prepare outcomes to twist their way, that their request not be fulfilled and their desires will not be.”
1235
A.D.
Radak Jewish
c. 1160–1235
ה' שומר את גרים. "The Lord preserves the strangers (or the converts).": The stranger (or the convert), the orphan, and the widow are weak because they have no helper, and He guards them. Therefore, the Torah warns about them in several places, and the Lord protects them. Similarly, He guards Israel, who were strangers among the nations and weak like an orphan and a widow. יעודד.: This means He will elevate them. ודרך רשעים יעות. "but the way of the wicked he makes crooked": Just as He elevates the weak, He will make the way of the wicked crooked; they will be pushed away and fall on it.”
Source

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“The Lord preserveth the strangers,.... The life of them, as he did the daughter of: the Greek, a Syrophenician woman, and a Samaritan, by healing them of their diseases, Mar 7:26; and in a spiritual sense he preserves the lives and saves the souls of his people among the Gentiles, who are aliens from the commonwealth of Israel, and strangers to the covenant of promise; for these he laid down his life a ransom, and became the propitiation for their sins; to these he sends his Gospel, which is the power of God to salvation unto them; he relieveth the fatherless and widow; in their distresses and troubles, who have no helper; a wonderful instance of his relieving a widow, in the most disconsolate circumstances, we have in raising the widow of Nain's son to life, and restoring him to his mother, Luk 7:12; in him "the fatherless", and all that in a spiritual sense are destitute of help in the creatures, and see they are so, "find mercy"; nor will he leave his people comfortless, or as orphans and fatherless ones, but will and does come and visit them, relieve and supply them with everything convenient for them; though his church here on earth may seem to be as a widow, he being in heaven at the right hand of God, yet he cares for her in the wilderness, and provides for her support, where she is nourished with the word and ordinances, and will be until he comes again; see Hos 14:3; but the way of the wicked he turneth upside down; so that they cannot find it; nor their hands perform their enterprise; their schemes and counsels are all confounded and blasted by him, and all their policy and power are not able to prevail against his church and people; see Psa 1:6.”
Source
1849
A.D.
1774–1849
“Strangers. He charges his people to be compassionate towards such, Exodus xxii. 21., and James i. 27. (Berthier) — We have been captives, Psalm cxii. 9. — Sinners, who have calumniated us, ver. 7. (Calmet)”
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.