The greatest stumbling block to men entering eternal life is the simplicity of salvation. Men want to “do” something to earn salvation, but God says it is a gift, because Jesus Christ paid the price on the cross. However, the gift must be received by faith.

The Philippian jailer asked Paul and Silas, “Sirs, what must I do to be saved?” To which they answered, “Believe in the Lord Jesus, and you shall be saved.” (ACT 16:30-31)
SALVATION’S SIMPLICITY

As simple as coming when called. 
Jesus said: “Come to me all who are weary and heavy-laden, and I will give you rest.” (MAT 11:28)
As simple as drinking water. Jesus said: “But whoever drinks of the water that I shall give him shall never thirst, but the water that I shall give him shall become in him a well of water springing up to eternal life.” (JOH 4:14) “If any man is thirsty, let him come to Me and drink.
He who believes in Me, as the scripture said, ‘from his innermost being shall flow rivers of living water…'” (JOH 7:37-38)
As simple as eating bread. Jesus said: “I am the bread of life, he who comes to Me shall not hunger, and he who believes in Me shall never thirst…. I am the living bread that came down out of heaven; if anyone eats this bread, he shall live forever; and the bread also which I shall give for the life of the world is my flesh.” (JOH 6:35, JOH 6:51)
As simple as entering a door. Jesus said: “I am the door, if anyone enters through Me, he shall be saved.” (JOH 10:9a)
As simple as receiving a gift. “For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.” (ROM 6:23)
As simple as calling for help. “For whoever will call upon the name of the Lord will be saved.” (ROM 10:13)
As simple as the trust of a child. “And He (Jesus) called a child to Himself and set him before them, and said, ‘truly I say to you, unless you are converted and become like children, you shall not enter the kingdom of heaven.'” (MAT 18:2-3)
As simple as believing in Jesus Christ. Jesus said: “Truly, truly, I say to you, he who believes (in Me) has eternal life.” (JOH 6:47)
“I am the resurrection and the life; he who believes in Me shall live even if he dies, and everyone who lives and believes in Me shall never die.
Do you believe this?” (JOH 11:25-26)
Each of the examples and illustrations is designed to show the simplicity of faith. The scripture says. “So faith comes from hearing, and hearing by the word of Christ.” (ROM 10:17)
Faith is trusting what the word of God says.
In the final analysis, it all comes down to the question in the above passage, “Do you believe this?” Your response will determine your eternal destiny; either heaven or hell.
Don’t stumble over the simplicity of the Gospel!