Summary: What does it really mean when Jesus said "Come Follow Me."
1. The Foundation of Discipleship is Obedience (v.46)
"Why do you call me, ’Lord, Lord,’ and do not do what I say?
We must remember that when Jesus preached this sermon, his audience stood in widening concentric arcs. Closest stood the freshly chosen Twelve. Around them spread a “large crowd of his disciples” and beyond them “a great number of people” from all various areas (Luke 6:17).
2. The True Disciple: Lays a foundation (v.47-48)
I will show you what he is like who comes to me and hears my words and puts them into practice.  He is like a man building a house, who dug down deep and laid the foundation on rock. When a flood came, the torrent struck that house but could not shake it, because it was well built.
a. He comes and hears and does (v.47)
b. He is like a builder (v.48a-c)
He builds a house (v.48a)
He digs deep (v.48b)
He lays a rock foundation (v.48c)
c. Result: It stands (v.48d)
3. The False Disciple: Lays No Foundation (v.49)
But the one who hears my words and does not put them into practice is like a man who
built a house on the ground without a foundation. The moment the torrent struck that
house, it collapsed and its destruction was complete."
a. He hears, but does not obey (v.49a)
b. He is like a builder (v.49b-d)
Builds a house (v.49b)
Does not dig (v.49c)
Lays no foundation (v.49d)
c. Result: A great fall (v.49e)
Conclusion:There was once a Shakespearian actor who was known far and wide for his one-man show of readings and recitations from the classics. He would always end his performance with a dramatic reading of the Twenty-third Psalm. Each night, without exception, as the actor began his recitation—The Lord is my shepherd, I shall not want—the crowd would listen attentively. And then, at the conclusion of the psalm, they would rise in thunderous applause in appreciation of the actor’s incredible ability to bring the verse to life. But one night, just before the actor was to offer his customary recital of Psalm Twenty-three, a young man from the audience spoke up. “Sir, do you mind if tonight I recite the Twenty-third Psalm?”
The actor was quite taken back by this unusual request, but he allowed the young man to come forward and stand front and center on the stage to recite the psalm, knowing that the ability of this unskilled youth would be no match for his own talent. With a soft voice, the young man began to recite the words of the Psalm. When he was finished, there was no applause. There was no standing ovation as on other nights. All that could be heard was the sound of weeping. The audience had been so moved by the young man’s recitation, that every eye was full of tears. Amazed by what he heard, the actor said to the youth, “I don’t understand. I have been performing the Twenty-third Psalm for years. I have a lifetime of experience and training—but I have never been able to move an audience as you have tonight. Tell me, what is your secret?” The young man humbly replied, “Well sir, you know the psalm…but I know the shepherd.”