When you decide how you live and act as the greatest authority of your own life...what are you doing? You're putting yourself in the position of God. You put yourself in God's judgment seat on the throne of your life where only God deserves to be.
Do you come to the Scriptures, do you come to the Lord seeking to learn with ears to hear, or do you come to substantiate your preconceived ideas about Him? Only when you come to God with an open heart, can you truly be changed by Him.
Proximity to Jesus Christ doesn't save a person. Familiarity with the scriptures or living a religious life or knowing a lot of religious people or doing a lot of religious things does not save a person. The only thing that saves a person is God's grace. That's the only thing.
Prayer testifies that spiritual power and spiritual ability is not in ourselves, but in God alone. Prayer is faithful reliance on God's power and not our power. So the action of going to prayer before our Father communicates to God our dependance on Him instead of ourselves.
The same God who created everything with words, gives us His Word. He gave us his word to reveal our sin, to reveal our need for salvation, and to show us that salvation is only found in Him. Don't deny His Word and what God says from His Word about our spiritual condition.
Judas was the one entrusted with the money. They looked around asking: Who's the one we can trust? Judas. Then he betrays Jesus. So yes, it is possible to be a Christian in the world's eyes, even in the church's eyes, even in your own eyes, and still be a child of perdition.
Throughout the New Testament, Jesus teaches us what is involved in being a faithful follower of Jesus. He's teaches the non-negotiables of discipleship. You have to deny yourself, take up your cross, and follow Jesus for the remainder of your days, once you are saved in Christ.