Because you can preach "the plan" all you want to, and if you don't preach "the man," you'll have converts to a system, not the Savior.
You can preach "the church" all you wish, and if you don't talk about the Bridegroom who purchased her with His blood, you'll be preaching narcissism.
You can preach against sin all year every year, and if you don't proclaim the One who died to save us from it and lived again so that we could live, you'll only be spreading guilt and despair and hoplessness - not the gospel.
You can preach about your experiences in life till the cows come home, but if you don't share His, will your church end up knowing more about your life on the farm than the Son you live for?
You can preach about biblical history, eschatology, pneumatology, soteriology, theology, or any other -ology ... but if you don't tell people about Jesus of Nazareth and what He taught and how He lived and how He reigns, just exactly what are you doing in the pulpit of a church in the Christian faith?
Have you actually shared all there is to know about Jesus of Nazareth, Son of God, Son of Man, Savior, Redeemer, Rabbi, Teacher, Lord, Master, Friend, High Priest, Sacrifice, Good Shepherd, the Holy and Righteous One, Firstborn of the Dead, Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace? The One to whom virtually all scripture points and praises - like John, His cousin - "Behold the Lamb of God who takes away the sins of the world!"
Has your church plumbed the depths of its relationship with God through Christ?
Have you told them all there is to know about His love; how far He would go and what He gave up?
Or have you given up?
Paul didn't give up, and Christ was all he resolved to preach (1 Corinthians 2:2).
Peter knew there was no other name that could save (Acts 4:12).
John knew that it is through Him that we have fellowship (1 John 1:5-7).
Not just a plan. Not just a church. Not just a history. Not just a theory of His return, His Spirit, His divinity, His salvation, or His relationship with His Father.
Have you actually worn out the Ancient of Days?
Have you truly out-taught the Teacher?
Have you really mastered the Master?
Now there were some Greeks among those who went up to worship at the Feast. They came to Philip, who was from Bethsaida in Galilee, with a request. "Sir," they said, "we would like to see Jesus." ~ John 12:20-21