25 And Adam knew his wife again, and she bore a son and named him Seth, “For God has appointed another seed for me instead of Abel, whom Cain killed.”
26 And as for Seth, to him also a son was born; and he named him Enosh. Then men began to call on the name of the Lord.
The name Seth means “appointed” or “substituted,” and indicates that Eve had faith that it was through this son that God’s promises would eventually be fulfilled. … In the days of [Enosh] (meaning “mortal frailty,” an implicit testimony to Seth’s awareness of man’s deep spiritual need), the son of Seth, it is recorded that “men began to call upon the name of Jehovah.” — Morris, page 149.
As sons continue to be born to man and the population of mankind consequently increases, so too does the presence, realization, and aftermath of depravity, with the result that the name of the Lord (a synecdoche for the Lord Himself) in increasingly invoked. The purpose of this invoking or “calling upon” the name of the Lord would therefore be to seek His aid in deliverance from death or distress, as is consistent with this expression elsewhere in Scripture (cf. 2 Kings 5:11; Psalm 116:4; Joel 3:5)—including as well the complementary idea of invoking the name of the lord as an act of worship in response to His acts of deliverance and sovereign self-revelation (cf. 1 Kings 18:39; Psalm 105:1; Zephaniah 3:9). The use of this expression thus adeptly serves to bring this section to thematic-theological closure, implying not only the increasing depravity of man—consistent with the overall theme of 1:1–11:26—but also, on the positive side, God’s continuing solicitude for the welfare of man and His increasing glorification via the worshipful response of those who receive and recognize His solicitude. — Wechsler, page 126.