The interpretation timeline
Luke 21:21 Douay-Rheims

Then let those who are in Judea, flee to the mountains; and those who are in the midst thereof, depart out: and those who are in the countries, not enter into it.

A.D. 339 – 1771 3 witnesses

Patristic

before A.D. 750
339
A.D.
c. A.D. 260–339
“Now our Lord, foreseeing that there would be a famine in the city, warned His disciples in the siege that was coming, not to betake themselves to the city as a place of refuge, and under God’s protection, but rather to depart from thence, and flee to the mountains.”
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“(ut sup.) And before this, Matthew and Mark said, And let him that is on the housetop not come down into his house; and Mark added, neither enter therein to take any thing out of his house; in place of which Luke subjoins, And let them which are in the midst of it depart out.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“And there shall be signs in the sun, and in the moon,.... They shall be darkened, and suffer very strange and surprising eclipses: and in the stars; they shall fall from heaven, as in Mat 24:29 and so the Ethiopic version reads here: all which, as it may be understood in a literal sense, so it may likewise in figurative and mystical one, and be interpreted of the changes there should be in the Jewish state; See Gill on Mat 24:29. So the Jewish writers (h) interpret the sun, the light, the moon, and stars, in Ecc 12:2. By the "sun" they understand the kingdom of the house of David; by "the light", the law; by "the moon", the sanhedrim; and by the stars, the Rabbins; and the same seem to be designed by the stars here: and upon the earth distress of nations; upon the land of Israel; in the several nations and countries belonging to it; as Galilee of the nations, Judea, and the region beyond Jordan, shall be in great distress: with perplexity; of mind, not knowing what to do, which way to go, or step to take; the Syriac version, instead of it, reads "clapping, or pressing of the hands"; which is done by persons, when in an agony and great distress: the sea and the waves roaring; which design some unusual and extraordinary storms and tempests, and inundations in the sea of Galilee, or Tiberias, which would be so very terrible, as to cause great uneasiness, distress, and perplexity; and so some versions render it, "because of the sea", &c. (h) In Prefat. Echa Rabbati, fol. 38. 4. Jarchi in Eccles. xii. 2.”
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.