Here, we see the first public preaching of the Gospel. Seth, the substitute, was born to Adam and Eve. He is the carrier of the Messianic promise since righteous Abel is dead and unbelieving Cain fled from the presence of the Lord into the land of Nod.
Names in the Bible have great meaning and significance. Seth means “compensation” or “appointed.” Eve names him this because “God has appointed 
another seed for me instead of Abel, whom Cain killed” (Gen. 4:25). Seth is a great light in the midst of the gloom caused by murder, legalism, and wickedness. Eve remembers the gospel, the good news, in the midst of sad days.
Seth, however, names his son Enos (or Enosh). Enos comes from the Hebrew root anash, “to be weak, sick.” Properly, Enos means, “mortal man.” Despite the joy of this birth, Seth keeps the wages of sin ever before his eyes. During the days of joy and goodness, Seth remembers that there is evil.
Why does Seth name his son, “mortal?” This is a solemn reminder that man forfeited his immortality due to his sin. He is now weak, sick, and death relentlessly pursues him. Even the newborn has one foot in the grave. Remember what the preacher says in Ecclesiastes 12:6-7.
And yet, in the days of Enos, the mortal man, men began to call upon the name of the Lord. This is a wonderful depiction of true worship in the Old Testament. Here, Moses uses a figure of speech called synecdoche. Synecdoche refers to a thing by the name of one of its parts, like referring to a car as your “wheels.” Here, Moses is using our response, “calling on the name of the Lord,” as a designation of the whole divine service, where God first serves us with His Word and sacraments, and then we respond with praise and thanksgiving.
This is necessary for us to understand, lest our worship devolves into only our response or only the sacrificial side of worship. St. Paul explains this in a fuller way in Romans 10:13-17. And so, when Moses uses the term “calling upon the name of the Lord,” he is also referring to the sacramental aspect of worship: preaching and teaching concerning the Messiah, the One Who would destroy the works of the devil.
Here, in the days of the “mortal” Enos, our God gave His church an added spiritual blessing, that they could meet in a definite place, preach, pray, and sacrifice. In short, our God gave Enos, the mortal man, the means by which mortality puts on immortality, and corruption puts on incorruptibility. Here, Seth urged all of his congregation, all of them “Enos,” to wait for their redemption, to believe the promise about the woman’s Seed.
This is why God so zealously defends the Third Commandment and why we so fervently pray for God’s kingdom to come among us. This is why we do not forsake the assembling of ourselves together, as is the manner of some. For this public preaching and teaching creates faith. Faith then calls upon the name of the Lord. And whoever calls on the name of the Lord shall be saved.
Worship is the only attribute which is ascribed to the Sethites. The Cainites were the great inventors. They invented musical instruments, domestic agriculture, and metallurgy. They were the Bill Gates and the Steve Jobs of the antediluvian world. But they were mortal; they died and have been found wanting before the judgment throne of Christ.
There are not many wise among us. There are not many plutocrats among us. We do not have the actors or the athletes. But what we do have is the one thing that will save us from sin and death. We have the one thing which will swallow up mortality forever. Men wither like grass, but the Word of the Lord endures forever. And this is the Word which by the gospel was preached to you.