Once you have sincerely asked Christ into your life, several areas will begin to change or develop. The rate of change will vary for each individual, but after some days/weeks/months if there is no change in heart attitude and behavior, a person should re-assess if they have actually become a Christian. True repentance is not just an attitude, but rather a transformational process.
If a person demonstrates no clear change in their lifestyle, habits, thoughts and words over a period of time, then little assurance can be given to them regarding their salvation. The Apostle Paul exhorted people to “Test yourselves to see if you are in the faith; examine yourselves! Or do you not realize this about yourselves, that Jesus Christ is in you – unless indeed you fail the test.” (2 Corinthians 13:5)
Some areas that you might expect to see change are the following:
A growing desire to read the Bible (Psalms 119:10), understanding of what you are reading, and a desire to apply what you are learning to your life.
A growing sense of God’s presence (Romans 5: 1-5), and gentle voice whispering to you to obey the Scriptures as they should apply to your life
A greater awareness of God’s holiness, one’s sin + motivation for doing things, plus a growing sorrow over anything which displeases God, leading to a quiet humility. (Psalms 51:1-17)
A growing sense that you are forgiven as you confess and repent (stop doing it!) from specific sins. (Psalms 32:1,2) Increasing manifestation of the ‘fruit of the Spirit which is love, joy, peace, patience, kindness, faithfulness, goodness and self-control, as you rely on God’s Spirit to fill you more each day, moment-by-moment. (Galatians 5:22,23)
A growing desire to pray and talk with your Father in heaven about everything, all the time. (I Thessalonians 5:17,18)
A growing desire to fellowship with like-minded believers in Bible study and churches (Hebrews 10:25), as well as to help those in need, especially other believers, but also non-believers.
A growing desire to share your faith in Christ with others as you depend moment by moment on the empowering of God’s Spirit. (1 John 4:2,3, Acts 1:8)
A growing strengthening of your faith; perseverance in the midst of suffering or persecution for your faith, and a desire to honor Him in all areas. (Acts 4:1-35)
A growing desire to give of your time, talents and resources to promote the kingdom of God. (Acts 2:44-47)
A growing desire to integrate one’s faith with all elements of one’s life, seeking to please God in all areas (2 Corinthians 5:9). For example, if the Bible clearly speaks about on issue, how will it affect your personal life and ethics? Your family life? Your business? The way and people you vote for? Think about it.
Again, a person who claims to be a Christian, but who does not demonstrate a deepening love for God manifested by allowing Christ to increasingly be Lord of their life may not be a true believer. For example, there are many terrible, hateful things done by religious people, including so-called Christians.
The Apostle John stated that a person who is not growing in love, but remains hateful, is not a believer. (1 John 3:15) The Apostle Paul stated in 2 Thessalonians 1:6-10, “… after all it is only just for God to repay with affliction those who afflict you, and to give relief to you who are afflicted and to us as well when the Lord Jesus will be revealed from heaven with His mighty angels in flaming fire, dealing out retribution to those who do not know God and to those who do not obey the gospel of our Lord Jesus. These will pay the penalty of eternal destruction, away from the presence of the Lord and from the glory of His power, when He comes to be glorified in His saints on that day, and to be marveled at among all who have believed — for our testimony to you was believed. (NASU)
In that case, if those people were to die this moment, they would go to hell rather than heaven, having chosen to live a false life, pretending to be a Christian. They gave themselves the ‘label’ Christian, but it was not true of their actual relationship with Christ Himself. God is love, and true Christians demonstrate more of this over time.
Finally, one fog-clearing question: “In a court of law, would there be enough evidence to convict you of being a true Christian?”