What must I do to be a Christian?
If you have not believed in Jesus as the Messiah, this is where your Christian life must begin, because the “natural man” (the man who has not believed in Jesus Christ) cannot accept or understand the Spiritual things of God.
“But a natural man does not accept the things of the Spirit of God; for they are foolishness to him, and he cannot understand them, because they are spiritually appraised.”
1 Corinthians 2:14
Every human being has sinned, meaning to violate the standards set by God, and the result of that sin is death (separation from God).
“for all have sinned and fall short of the glory of God,” Romans 3:23 “For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.” Romans 6:23
Salvation is by faith alone in Christ alone. Good works will not save.
“For by grace you have been saved through faith; and that not of yourselves, it is the gift of God; not as a result of works, that no one should boast.” Ephesians 2:8-9 “But when the kindness of God our Savior and His love for mankind appeared, He saved us, not on the basis of deeds which we have done in righteousness, but according to His mercy, by the washing of regeneration and renewing by the Holy Spirit,” Titus 3:4-5
Faith is only as good as its object. Therefore, the object must be worth believing in. For your soul to be eternally saved from spiritual death requires you to believe that Jesus is the Messiah, namely: that He died for your sins, was buried and rose again on the third day. It is putting your trust in the finished work of the Lord for personal deliverance from the Lake of Fire.
“For I delivered to you as of first importance what I also received, that Christ died for our sins according to the Scriptures, and that He was buried, and that He was raised on the third day according to the Scriptures, and that He appeared to Cephas, then to the twelve.”
1 Corinthians 15:3-5
There is no “work” you can do to be saved other than the “work of faith” that is to believe in the Person and Work of Jesus the Messiah.
“They said therefore to Him, ‘What shall we do, that we may work the works of God?’ Jesus answered and said to them, ‘This is the work of God, that you believe in Him whom He has sent.’" John 6:28-29
Once you have believed, you are a new creation that is designed for good works.
“For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.” Ephesians 2:10