The interpretation timeline
Proverbs 30:9 Douay-Rheims

Lest perhaps being filled, I should be tempted to deny, and say: Who is the Lord? or being compelled by poverty, I should steal, and forswear the name of my God.

A.D. 379 – 1871 5 witnesses

Patristic

before A.D. 750
379
A.D.
Basil of Caesarea Patristic
c. A.D. 330–379
“Solomon says, "Give me neither beggary nor riches; give me only what is necessary and sufficient," lest being filled I should deny and say, Who sees me? Or being poor, I should steal and forswear the name of my God; thus representing riches as satiety, poverty as a complete lack of the necessities of life, and sufficiency as a state both free from want and without superfluity. Sufficiency varies, however, according to physical condition and present need.… In every case, care must be taken for a good table, yet without overstepping the limits of the actual need.”
Source
397
A.D.
Ambrose of Milan Patristic
A.D. 339–397
“Therefore, pay attention to yourself, poor man, pay attention, wealthy man; because there are trials in both poverty and riches. And therefore the Wise Man says: Do not give me riches or poverty, give me only what is sufficient for me. Because riches, like feasts, stretch the stomach and the mind with worries and anxieties. And therefore he asks to be established with what is necessary and sufficient: Lest, he says, being filled, I become a liar and say: Who sees me? But if I become poor, I will commit theft and swear in the name of the Lord (Ibid.). Therefore, the temptations of the world must be avoided and guarded against; lest the poor despair and the wealthy become arrogant.”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“lest I become sated from wealth. and deny the existence of the Holy One, blessed be He, out of my extreme haughtiness. Now what is the denial? And I say, “Who is the Lord?” Meaning, there is no God. and take hold of the name of my God to become accustomed to swearing by it falsely.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Lest I be full, and deny thee,.... This is the dangerous consequence of riches, and the temptation they expose men unto; who, being full of the things of this world, are tempted to deny the Lord; not his being and perfections directly, but chiefly his providence; to deny that what they have, they have received of him, but attribute it to their own care, diligence, and industry; and now think they can live without him, without any dependence on his providence, having a large affluence of the things of life: yea, they may be said to deny him, when they forget the bounties of his providence; are not thankful to him for them; that flatter themselves with a continuance of them, without any regard to him, as if he had no concern in the affairs of life; see Deu 32:15; and say, Who is the Lord? as Pharaoh did, Exo 5:2. I am not obliged to him; I can live without him, I have enough of my own; or lest I be poor, and steal, and take the name of my God in vain; this is the snare that attends poverty; men, for want of food and raiment, are tempted to steal from their neighbours, which is a sin against the law of God, the eighth command; and then to cover the theft, when an oath is offered to purge them from the charge and suspicion of it, they take it, and so are guilty of false swearing, or taking the name of God not only in vain, but falsely, and so become guilty of the breach of the third command. Agur, a good man, is desirous he might not be exposed to temptations to such evils, and especially which so affected the honour and glory of God.”
Source
1871
A.D.
1871
“be full . . . deny--that is, puffed up by the pride of prosperity. take the name . . . vain--This is not (Hebrew) the form (compare Exo 20:7), but "take" rather denotes laying violent hold on any thing; that is, lest I assail God's name or attributes, as justice, mercy, &c., which the poor are tempted to do.”
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.