Isaiah 19:18

In that day. That is, when Egypt has learned the folly and futility of opposition to the will of God (v. 17). Compare the same expression in Isa. 2:11, 17; 4:2; 26:1; 29:18; 52:6; Joel 3:18; Zech. 2:11; 9:16; 12:8; 13:1; 14:4, 9; Mal. 3:17. “In that day” appears to be a technical expression of the prophets in regard to the time when God reveals Himself to the nations and sets up the Messianic kingdom. The remainder of Isa. 19 (vs. 18-25) constitutes a conditional prophecy of the time when, according to God’s original plan for the evangelization of the world (see pp. 29, 34), the Egyptians should come to a knowledge of the true God and should serve Him as the Hebrew people did (see v. 25).

Five cities. Either five specific but unnamed cities (Heliopolis, Leontopolis, Elephantine, Daphnae, and Memphis have been suggested) or simply a round number. From among the heathen Egyptians, who had long rejected the message of God’s grace, many would turn to the Lord and learn the “language” and ways of God’s people (see p. 29). In Zeph. 3:8-10 a similar picture is presented (see also Zech. 14:16-19).

Swear. That is, swear an oath of allegiance to the Lord, acknowledging Him as the true God.

The city of destruction. Heb. ‘ir haheres, literally, “the city of the destruction.” Fifteen Hebrew manuscripts, the Dead Sea scroll lQIs, Symmachus’ version of the LXX, the Vulgate, and the Arabic read ‘ir hacheres, or its equivalent, “the city of the sun.” The name of the Egyptian city of Heliopolis means “City of the Sun.” Heliopolis is the Greek name for the city of On, mentioned in Gen. 41:45, 50. It was situated near the eastern bank of the Nile, 19 mi. north of Memphis (Noph; see Isa. 19:13), and almost due west of the northern end of the Gulf of Suez. Jeremiah (Jer. 43:13) refers to the city as Beth-shemesh, Hebrew for “House of the Sun.” This city was the center of sun worship. If the reading ‘ir hacheres is correct, Isaiah is commenting on the fact that of the “five cities” that “swear to the Lord of hosts” one would be the City of the Sun, the erstwhile center of Egyptian sun worship.