Oh, my God, I would be devastated if the Lord said to me on that day, "I never knew you; depart from Me"! What a calamity that would be. Jesus made it clear that "Not everyone who says to Me, Lord, Lord, shall enter the kingdom of heaven; but he who does the will of My Father in heaven". This means we have the responsibility to ensure that we are in the kingdom of heaven. How do we know or make sure that we are in the kingdom of heaven? This book helps us to determine that. Jesus made some alarming statements such as, "Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat. Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it". This implies that many people are on the wrong path and do not know it. This book examines and explains the keys that we should use to ensure that we enter the kingdom of heaven and gain eternal life. It highlights the instructions given by our Lord Jesus to the apostles to teach us all how to gain eternal life and it examines whether or not after Jesus ascended to heaven the apostles were obedient and carried out the instructions given.