Revelation 3:20 is addressed to Christians, inviting them to "open the door" and allow Christ to enter into close fellowship. It is addressed to Christians and concerns their fellowship with Christ, not to non-Christians concerning their salvation.
What term or phrase does the Bible use to mean salvation?
In evangelizing the lost, speak the language the Bible speaks. The Book of John explains how to receive the gift of eternal life. John, in fact, identifies the purpose of his book: "But these are written that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in His name" (20:31).
How does one receive that eternal life? The word that John uses ninety-eight times is believe. Prior to raising Martha's brother, Lazarus, from the grave, Christ explained to her, "I am the resurrection and the life. He who believes in Me, though he may die, he shall live. And whoever lives and believes in Me shall never die" (John 11:25-26). Believe means, "Understanding that Jesus Christ died for me and rose again, I receive eternal life by trusting Him alone as my only way to heaven."
A woman who attended a liberal church once asked her pastor, "If I watch a John Wayne movie, is God more likely to let me into heaven?" She sincerely thought that John Wayne was a good friend of Jesus Christ and watching one of his movies would increase her chance of getting into heaven. We might laugh at her logic, but we're just as mistaken to think that church attendance, baptism, keeping the commandments, taking the sacraments, or any amount of good living can get us into heaven. God asks us to trust a person—Jesus Christ—as our only means of salvation.
Does the Bible use other terms to convey the idea of appropriation? Consider the following:
- Nicodemus was told to look and live (John 3:14-15).
- The Samaritan woman was told to ask (John 4:10).
- The Jews were told to come to Christ (John 5:40).
- The multitudes were told to believe in Christ (John 6:47).
- They were also told to eat His flesh and drink His blood (John 6:53-54). Note: This is in the context of Christ being the "Bread of Life" (cf. John 6:35).
- The Pharisees were told to keep His Word (John 8:51).
- Others were told to look at Christ as a door and enter in (John 10:9).
Each contains the idea of appropriation. The thought conveyed is, "Recognizing that Christ alone is my only way to eternal life, I take Him at His Word and trust Him to save me."
The Gospel of John never exhorts one to "invite Jesus into your heart." The phrase is not used in Scripture in evangelizing the lost.