The interpretation timeline
Psalm 105:18 Douay-Rheims

And a fire was kindled in their congregation: the flame burned the wicked.

A.D. 430 – 1849 4 witnesses

Patristic

before A.D. 750
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“"And the fire was kindled in their company; the flame burnt up the sinners" [Psalm 106:18]. This word is not in Scripture usually applied to those, who, although they live righteously, and in a praiseworthy manner, are not without sin. Rather, as there is a difference between those who scorn and scorners, between men who murmur and murmurers, between men who are writing and writers, and so forth; so Scripture is wont to signify by sinners such as are very wicked, and laden with heavy loads of sins.”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“And fire burned (Num. 16:35) “and consumed the two hundred and fifty men who burnt the incense. “”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“And a fire was kindled in their company,.... This seems to be the company of Korah, or however a part of it, the two hundred and fifty men that had censers, and so were of the Levitical race, as Korah was; this fire came from the Lord out of heaven. The flame burned up the wicked; the two hundred and fifty men with censers, Num 16:35, this was an emblem of that fire which shall consume those that hurt the witnesses; or of that vengeance of eternal fire which wicked men will suffer for ever.”
Source
1849
A.D.
1774–1849
“Wicked. Two hundred and fifty accomplices, (Numbers xv. 35.; Calmet) and fourteen thousand seven hundred murmurers. (Menochius)”
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.