In answering this question, I want to go much deeper than just the obvious answer, which would be that deception is just a lie. Since we are looking into the subject of being born again, I would like to review and attempt to answer this question as it relates to our view of God and to our heart and mind concepts of who we think He is. I believe to receive the experience that we desire as a result of our faith toward God we must be convinced that God is truth and His word is the absolute truth. If you've been mislead through false teachings about God or your concept of Him has been confused, His word remains true. That is why it is so important for you to become born again and begin to read the Bible to get answers from God Himself.
I would like to expose deception by helping you realize that we all have been influenced by it. What has your concept of God been in your life? Does He seem like a God that is unreachable? Do you see Him as a big judge ready to thump you when you make a small or a major mistake? Do you see God as a greater power, yet without the ability to understand who He is? Are you filled with doubts that He could really help you even though you believe He exists? Are you skeptical about Him because of the obvious events of terrorism, wars, and starvation in our world? Do you believe in Him at all? And if you are not sure you believe, who influenced you to doubt? Was it your own heart, or have you been influenced by some other source of power that you don’t understand? If you don’t believe in God, has it helped you to get through life any better? Are you afraid that believing in God could somehow affect your life? If you have considered giving your heart to Him, are you afraid of giving up your rights to do what you want to do even though it may be hurting you and other people’s lives? To say it another way, are you afraid to make that commitment because you don’t really want to turn loose of your sinful life and live for Him? You may be afraid of what He will do with your life once you give it to Him. I can assure you that I know that I serve the Lord Jesus, who I am truly convinced, knows best what to do with my life! When you become intimately involved with God, you will soon see that He is a great and loving Father, and eager to rescue your life from the deceptions of this world. He can be totally trusted.
We could ask many more questions about what you believe and why. The very fact that you think about who God is and what His place is in your life does prove that He is trying to reach you in whatever circumstances you face because He loves you. I believe that when you make that decision to invite Him into your heart that He then begins to reveal more truth about Himself and the truth about your own heart and what you believe. He will then begin to show you the difference between having a relationship with Him rather than just having a powerless relationship with some dead religion that doesn’t seem to be helping people out of their darkness and into His light.
Excerpts from my book "Are you saved or deceived?"

If you are deceived in your heart, you don’t know it. If you knew that you were deceived then it would not be deception. Let’s define deception as something you believe to be true...or ok, that is false. I realize if you have been deceived for many years and then you come to the knowledge of the truth, this can also be somewhat disheartening. However, God can restore the years that you have missed out on His grace and blessings. It’s a very sad but true realization that in America there are many pastors and religious leaders who are not born again. They may have a piece of paper that gives them a license to be a preacher, but if they are not saved by the grace of God and do not have the knowledge to lead another to the saving grace of Jesus Christ, then what good are they doing in our society as leaders of churches?  If you are a pastor and God is not showing up in your church to effect change on the hearts of sinful and seemingly righteous men, then all you have is fruitless religion.
Division...a word that has been coming to me for a few weeks as I am always praying about these entries.
Living a life yielded to willful sin will make you vulnerable to deception, and will build up walls of division between you
and God. As a result you become a wanderer, wondering about what place God has in your heart and life.
In your unwillingness to offer your life to God so that he can establish  freedom for you, you become the culprit
in hindering  your own destiny in His purpose for you.
How marvelous though is God, that in His love He will continue to hold out His hand and offer to carry you through
whatever struggle you are facing. This is a harsh world with harsh people in it, and it takes a heart of compasion and insight 
to live in it on a daily basis and not give in to discouragment.  Begin to yield to the things that you already know God is wanting
you to do.  He is our Father and we are His children. He is looking for obedience from us so He can pour out His support and favor on us. I believe we all can benefit by getting all the favor we can get, and mostly that God will be pleased when He looks upon us with His favor.