The interpretation timeline
Ruth 2:2 Douay-Rheims

And Ruth the Moabitess said to her mother in law: If thou wilt, I will go into the field, and glean the ears of corn that escape the hands of the reapers, wheresoever I shall find grace with a householder that will be favourable to me. And she answered her: Go, my daughter.

A.D. 397 – 1849 5 witnesses

Patristic

before A.D. 750
397
A.D.
Ambrose of Milan Patristic
A.D. 339–397
“Does the widow Naomi seem to you of small account, who supported her widowhood on the gleanings from another's harvest, and who, when heavy with age, was supported by her daughter-in-law? It is a great benefit both for the support and for the advantage of widows that they so train their daughters-in-law as to have in them a support in full old age, and, as it were, payment for their teaching and reward for their training. For to her who has well taught and well instructed her daughter-in-law a Ruth will never be wanting who will prefer the widowed life of her mother-in-law to her father's house, and if her husband also be dead, will not leave her, will support her in need, comfort her in sorrow and not leave her if sent away; for good instruction will never know need. So that Naomi, deprived of her husband and her two sons, having lost the offspring of her fruitfulness, did not lose the reward of her pious care, for she found both a comfort in sorrow and a support in poverty.”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“I will go now to the field To one of the fields of the people of the city, after one of them, in whose eyes I will find favor, that he will not rebuke me.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“And Ruth the Moabitess said to Naomi,.... After they had been some little time at Bethlehem, and not long; for they came at the beginning of barley harvest, and as yet it was not over, nor perhaps for some time after this; and knowing and considering the circumstances they were in, and unwilling to live an idle life, and ready to do any thing for the support of her life, and of her ancient mother-in-law; which was very commendable, and showed her to be an industrious virtuous woman: she addressed her, and said: let me now go to the field; she did not choose to go any where, nor do anything, without her advice and consent; so dutiful and obedient was she to her, and so high an opinion had she of her wisdom and goodness; she desired to go to the field which belonged to Bethlehem, which seems to have been an open field, not enclosed, where each inhabitant had his part, as Boaz, Rut 2:3 though Jarchi interprets it of one of the fields of the men of the city; hither she asked leave to go, not with any ill intent, nor was she in any danger of being exposed, since it being harvest time the field was full of people: her end in going thither is expressed in the next clause: and glean ears of corn after him, in whose sight I shall find grace; or "in" or "among the ears of corn" (o); between the ears of corn bound up into sheaves, and there pick up the loose ears that were dropped and left. This she proposed to do with the leave of the owner of the field, or of the reapers, whom she followed; she might be ignorant that it was allowed by the law of God that widows and strangers might glean in the field, Lev 19:9 or if she had been acquainted with it by Naomi, which is not improbable, such was her modesty and humility, that she did not choose to make use of this privilege without leave; lest, as Jarchi says, she should be chided or reproved, and it is certain she did entreat the favour to glean, Rut 2:7. and she said unto her, go, my daughter; which shows the necessitous circumstances Naomi was in; though perhaps she might give this leave and direction under an impulse of the Spirit of God, in order to bring about an event of the greatest moment and importance, whereby she became the ancestor of our blessed Lord. (o) , Sept. "in spicis", Montanus, Drusius, Piscator; "inter spicas", De Dieu, Rambachius.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Glean ears of corn - The word glean comes from the French glaner, to gather ears or grains of corn. This was formerly a general custom in England and Ireland; the poor went into the fields and collected the straggling ears of corn after the reapers; and it was long supposed that this was their right, and that the law recognized it. But although it has been an old custom, I find that it is now settled, by a solemn judgment in the court of common pleas, that a right to glean in the harvest field cannot be claimed by any person at common law; see Law Dictionary, article gleaning. Any person may permit or prevent it in his own grounds. By the Irish acts, 25 Hen. VIII., c. 1, and 28 Hen. VIII., c. 24, gleaning and leasing are so restricted as to be in fact prohibited in that part of the United Kingdom. See the note on Lev 19:9. After him in whose sight I shall find grace - She did not mean Boaz; but she purposed to go out where they were now reaping, and glean after any person who might permit her, or use her in a friendly manner. The words seem to intimate that, notwithstanding the law of Moses, the gleaners might be prevented by the owner of the field.”
Source
1849
A.D.
1774–1849
“To me. It was the privilege of the poor and of strangers to glean, Deuteronomy xxiv. 19., and Leviticus xix. 9. Yet Ruth asks leave, through civility. (Calmet) — This law is no longer in force, but it would be inhuman for the rich to deny this liberty to those who are in distress, and willing rather to work than to beg. (Tirinus)”
Source
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.