In a very interesting verse, Genesis 4:26, we are told that a son was born to Seth, “and he called his name Enos: then began men to call upon the name of the LORD.” The great Hebrew scholar Cassuto said of this verse, “There is a parallelism of both language and theme: a human being is called by a name suited to him—Enosh; and God is called by a name befitting Him—LORD (YHWH).” To understand what it means to call on the name of the Lord, we must understand this verse.
Enos or Enosh means mortal. Seth thereby defined man. He had come to know that fallen man was born to die, and he gave his son that name as a sign. It was a reminder to a loving father that the best of children are born into a world of sin and death. It was also thereby a witness that there is no hope in man, or in generation, only in regeneration. Seth thus defined all men, including himself, as a witness to his faith.
At the same time, “then began men to call upon the name of the LORD.” The name of the Lord is a name God declared and revealed concerning Himself, beginning in Eden (Gen. 2:7), but most fully to Moses (Exod. 3:13–14). It means
He Who Is, the self-existent and eternal God.
This means that to call upon the name of the Lord is much more than prayer and worship. It means to know Him as He is, as He reveals Himself in His Word. Instead of approaching God in terms of our thinking, we approach Him only in terms of His Word and revelation.
Seth no doubt at times called his son, “my darling boy,” “son,” and other loving terms, but, by naming him Enos, he always reminded himself what man really is, all men, including his beloved son and himself.
Similarly, many people approach God, not in terms of His name, but in terms of their wishes. Some years ago, in the 1950s, a prominent actress spoke of God as “a living doll.” She was not calling on the name of the Lord, only her imagination.
To call on the name of the Lord is to see Him only in terms of His Word and His Son. The living God is the God who has named Himself, and revealed Himself. Call only upon Him. Or will it be said of us, as Isaiah said of the worshippers of his day, “[T]here is none that calleth upon thy name” (Isa. 64:7)?
Taken from A Word In Season: Daily Messages on the Faith for All of Life, Volume 7, pp. 46-47.

- R. J. Rushdoony
Rev. R.J. Rushdoony (1916–2001), was a leading theologian, church/state expert, and author of numerous works on the application of Biblical law to society. He started the Chalcedon Foundation in 1965. His Institutes of Biblical Law (1973) began the contemporary theonomy movement which posits the validity of Biblical law as God’s standard of obedience for all. He therefore saw God’s law as the basis of the modern Christian response to the cultural decline, one he attributed to the church’s false view of God’s law being opposed to His grace. This broad Christian response he described as “Christian Reconstruction.” He is credited with igniting the modern Christian school and homeschooling movements in the mid to late 20th century. He also traveled extensively lecturing and serving as an expert witness in numerous court cases regarding religious liberty. Many ministry and educational efforts that continue today, took their philosophical and Biblical roots from his lectures and books.