Does a person have to fully understand the gospel to go to heaven?

from the old testament

• Salvation has always rested on trusting God’s promises rather than fully understanding every detail. Abraham was counted righteous because of his faith, not because he grasped every future plan of redemption (Genesis 15:6).
• The Israelites were saved during the first Passover by applying the blood of the lamb in obedience, even though they did not yet comprehend how it pointed to Christ (Exodus 12:7,13).
• Proverbs 3:3-5 says, “Trust in the Lord with all your heart, and do not lean on your own understanding. In all your ways acknowledge him, and he will make straight your paths.” We may not understand everything in life, but we must trust in God anyway.

from the new testament

• In one sense, the gospel message is a simple one: Jesus died for the forgiveness of our sins and was resurrected on the third day (1 Corinthians 15:3-4; Romans 4:25). Yet, as simple of a sentence as that is, the truth and implications it contains are quite profound (John 3:16; Colossians 1:13-14).
• Our understanding of the gospel comes by hearing it preached (Matthew 28:18-20; Romans 10:13-17).
• Paul describes the process of understanding the gospel as starting with preaching, which leads others to hear, understand, believe, and reach out to God for salvation(Romans 10:14).
• We must understand the individual components of the gospel story to put our faith in the gospel and in Jesus Christ: His deity, virgin birth, sinless life, and His physical death, burial, and resurrection. We don't have to understand how these events were possible, but we do have to believe that they happened and understand that with God all things are possible (Matthew 19:26).
• Even children can understand the gospel. Jesus said, "Let the little children come to me, and do not hinder them, for to such belongs the kingdom of God" (Mark 10:14). Yet at the same time, no one will ever fully understand the ways of God. As Paul notes, “Oh, the depth of the riches and wisdom and knowledge of God! How unsearchable are his judgments and how inscrutable his ways!” (Romans 11:33).
• Put simply, to go to heaven, all we have to do is this: "believe in the Lord Jesus, and you will be saved" (Acts 16:31). When we hear the gospel and understand it, we have to choose to believe it. We trust in Jesus' sacrificial death, burial, and resurrection on the third day as the one and only way for us to receive salvation.
• When we believe in Jesus' name, we are saved: "But to all who did receive him, who believed in his name, he gave the right to become children of God" (John 1:12). This is the simple yet profound truth of the gospel.

implications for today

Knowledge of the gospel differs from understanding of it. Knowledge stays in the head, but understanding can lead to transformation. People can have knowledge of the gospel without putting their faith in it. This does not count toward their eternal salvation. The Ethiopian eunuch (Acts 8:26-39), Cornelius (Acts 10), Apollos (Acts 18:24-28), and the twelve men in Ephesus (Acts 19:1-7) are biblical examples of people who had personal religious history, but their salvation only came when they chose to put their faith in Christ. They had to both hear and understand the gospel.

We do not have to understand every spiritual doctrine and facet that the gospel message entails to be eternally saved. We choose to believe God and the gospel even though there will always be facets that are a mystery to us. Anyone can understand the basic truth of the gospel. We believe that if anyone is mentally incapacitated God will extend His grace to them. As we grow in our faith, we gain better knowledge and understanding on other scriptural and doctrinal topics.