“Then he [Peter] began to call down curses on himself and he swore to them, ‘I don't know the man!’ Immediately a rooster crowed. Then Peter remembered the word Jesus had spoken: ‘Before the rooster crows, you will disown me three times.’ And he went outside and wept bitterly.”
Matthew 26:74-75 NIV
Have you come before the LORD Jesus Christ and God the Father and wept bitterly of your sins? Have you ever been emotionally drained of yourself in repentance to the LORD? If not, then if I were you, I would re-evaluate my relationship with God and the LORD Jesus. You see, many "so-called" Christians acknowledge that Jesus is the Christ, but so do the demons.
Demons Acknowledge Christ
"Moreover, demons came out of many people, shouting, 'You are the Son of God!' But he rebuked them and would not allow them to speak, because they knew he was the Christ."
Luke 4:41 NIV
By the way, for 20+ years, I was one of those "so-called" Christians and did enormous damage to Christianity. It is not enough to acknowledge Jesus is the Son of God. You have to repent of your sins and put your FAITH in Jesus Christ alone. This is a life-changing event that will be witnessed by all those around you. The Holy Spirit will enter you and fill you up. He will lead you to break the habits of your old self. We are too weak to do this on our own.
Become a Child of God
"Yet to all who received him, to those that believed in his name, he gave the right to become children of God."
John 1:12 NIV
Once you have really accepted Christ and put your total trust in Him, you will want to be baptized through a Believer's Baptism.
Be Baptized and Obey Jesus
[Jesus said,] "Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age."
Matthew 28:19-20 NIV
You can tell if a person who claims to be a Christian is a True Christian. If a person claims to be a (True) Christian, you will see all sorts of evidence of Christianity in his/her life. Many "so-called" Christians will give the appearance of being a True Christian and might even attend church. But it's not about attending church, even though we should belong to a church. It's about the heart, whether the person has accepted Jesus Christ as Lord of his/her life, and has put the Father, Son, and Holy Spirit first in his/her life.
Do you know someone who has a foul mouth that claims to be a Christian?
Do you know someone who is involved in promiscuous behavior that claims to be a Christian?
Do you know someone who is involved in alcohol/drugs that claims to be a Christian?
Do you know someone that is engaged in any other type of sinful lifestyle that claims to be a Christian?
My suggestion is if you know someone who claims to be a Christian and is engaging in any of the above behaviors that are inconsistent with Christianity, bring the issue before the person in private. Watch how the person reacts. If s/he asks for forgiveness and changes his/her ways, then you might have helped a True Christian see the error of his/her way. Thank you for helping to stop the damage of that message to unbelievers. But if the person says something silly such as, "Oh, I'll just ask for forgiveness on Sunday," that person is definitely a "so-called" Christian (or Christian in Name Only). Someone who has Jesus as the priority in his/her life will not want to sin ever, and will be open to correction.
Jesus Called Them Hypocrites
[Jesus said,] "Why do you call me 'Lord, Lord,' and not do what I say?"
Luke 6:46 NIV
James Says Do Not Deceive Yourselves - Do What the Word Says
"Therefore, get rid of all moral filth and the evil that is so prevalent and humbly accept the word planted in you, which can save you. Do not merely listen to the word, and so deceive yourselves. Do what it says."
James 1:21-22 NIV
John Says "So-Called" Christians or Christians In Name Only Lie
"If we claim to have fellowship with him yet walk in darkness, we lie and do not live by the truth."
1 John 1:6 NIV
The "so-called" Christians or Christians in Name Only are the ones that the world sees and claims that Christians are a bunch of hypocrites. While all of us fall short of the glory of God and cannot cast stones at others, the True Christian's heart with the priority of Jesus Christ in the core of his/her being is what separates him/her from the "so-called" Christian.
So what is it a person must do to be a True Christian?
First, you must acknowledge the sin in you life. Don't attempt to mask it or justify your actions. Admit that you are a sinner and confess your sins (all of them) to God. If you are engaged in any behavior that is sinful, you must be willing to end it. This repentance should be a very emotional (and possibly lengthy) process. One who is truly sorry will weep as Peter did. Beg forgiveness of God Almighty.
Second, ask Jesus to intercede in your life. Ask Him to be your Savior. Only through the blood of Jesus Christ are our sins able to be forgiven. Ask Jesus to come into your heart and live inside of you. When you do this, you will become a child of God.
Third, be obedient to the Lord Jesus by being baptized in the name of the Father and of the Son and of the Holy Spirit.
Fourth, obey Jesus' commands and teachings. Love God with all your heart, all your might, and all your soul. And love your neighbor as yourself. Keep yourself pure in heart, and do God's work here on earth. Learn the Ten Commandments, and put them into practice. And share your testimony with others.
I personally know many, many True Christians that walk the walk of Christianity. They praise their Savior Jesus Christ and live a life with Him as their #1 priority. I can assure you that no one would call any of them hypocrites with any justification. Surround yourself with True Christians, and you will witness the light of Jesus Christ in their lives.
I pray for your salvation. Come to the feet of God today and repent. Jesus is waiting on your call. He loves you so much that He died for you!