Respectfully, many call themselves Christians. We now have homosexual Christians, drunkard Christians, Muslim Christians, etc. Jesus clearly shows that just “answering” an alter-call or “praying a prayer” is not enough. A person must turn from iniquity. Psalm 19 warns that a person can step over a line, or let go of God. God is a faithful husband who will not forsake us, but that does not mean that we can’t divorce him! (Isaiah 50)
Naw...Once you are indwelt with the Holy Spirit and he is sealed in you and you in him, there's no way for him to leave...You're stuck with him...And he's stuck with you...
Christianity is not like joining the Boy Scouts or the Masonic Lodge or the Catholic Church...Christianity is a Spiritual Operation that Jesus performs on those who come to him in belief and trust...We can't unperform that operation...
Back to what you originally wrote:
Not true. Matthew 7:21-23 shows that many Christians will not go to heaven.
Your statement above conflates those who merely call themselves Christian with those who actually are Christians in faith and practice.
Those who just call themselves Christians are not in fact Christians by merely having said so.
There is not one true Christian who will not go to heaven, because, speaking of those who are true Christians ... "He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness."
FReegards!