And to Seth, to him also there was born a son; and he called his name Enos: then began men to call upon the name of the LORD. Genesis 4:26 (KJV)
The fall of man had taken place and is still visible in 2018. I see it in myself. I see it in people throughout the world via television news, and I know the fallenness of man is fact, truth. There is none who are good or practice righteousness (Psalm 14:2-3; Romans 3:23). We all need the LORD, and we all need to call on His name.
Cain had recently murdered Abel, a just man who had believed God, and Cain was apparently jealous of God’s approval of Abel’s offering to God; and in a fit of rage killed him. Cain was sent away from the “Presence of the LORD” (Genesis 4:16). The presence of the LORD is what the people of God want.
I would suppose that the people calling on the name of the LORD was due to the fact that many of these people; descendants of Adam and Eve; realized that they needed to call on the name that is above every name. They realized that the word to Adam and Eve concerning their coverings after the fall was a promise of a Savior, the Messiah who would come and redeem mankind from our sins.
When is the right time to call on the name of the LORD? When you realize that you are a sinner in need of God, His mercy, and His grace. Call upon Him now (2 Corinthians 6:2). Call upon the name of Jesus Christ the Son of God, God the Son.