Man is made in the image of God and is made to believe in God. The Bible is the codified living Word of God intended to bring man back to eternal life. Jesus Christ is the One who resurrects our souls. So preach Jesus Christ to lost souls. They are made to hear this message.
The opposite view is to labor in the ills of the culture. However, the culture has no light; the lost souls lives in the culture and demonstrates the death of the culture by his life. He probably knows the culture better than you if you have been saved and sanctified for some time.
Why preach the culture to him then? James writes, ‘Friendship with the world is enmity towards God” [James 4:4]. Why would you want to preach and labor in that which is an enemy of God?
Preach Jesus Christ and everything about Him. Begin with creation, the fall, the promised of His coming in Genesis 3:15, how you see Him foreshadowed in Noah, Joseph, Moses, etc. There is so much to be said about the Christ that you could spend your entire life preaching Him. The intent of the Bible appears to be to provide a lifetime supply of teaching on Him.
Thus put your sermon preparation effort into knowing the Christ of the Scriptures, Old & New, and preach and teach Him. After all, He is our Lord and Savior, and we ourselves should hunger and thirst after Him and therefore be able to easily preach Him since we know Him personally.