Why Jesus Christ Said - Come?

Many came to Christ with full of doubt and went back sorrowfully, But only few of them came with an acknowledgement that Jesus Christ alone is God.

Peter is one of them who acknowledged that Jesus Christ is God, and Church must be built on that faith so that the Hades shall not prevail it - Jesus answered and said to him, Blessed are you, Simon Bar-Jonah, for flesh and blood has not revealed this to you, but My Father who is in heaven. And I also say to you that you are Peter, and on this rock I will build My church, and the gates of Hades shall not prevail against it. And I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven - Matthew 16:16-19

The disciples were struggling in the midst of the ocean for more than 6 hours, and they could not believe when they saw Jesus at their death point situation - Immediately Jesus made His disciples get into the boat and go before Him to the other side, while He sent the multitudes away. And when He had sent the multitudes away, He went up on the mountain by Himself to pray. Now when evening came, He was alone there. But the boat was now in the middle of the sea, tossed by the waves, for the wind was contrary. Now in the fourth watch of the night Jesus went to them, walking on the sea. And when the disciples saw Him walking on the sea, they were troubled, saying, “It is a ghost!” And they cried out for fear - Matthew 14:22-26

But the Question Peter asked has so much meaning that Jesus Christ alone can make us to walk on the water, no other God or Demons can do such a thing - But immediately Jesus spoke to them, saying, Be of good cheer! It is I; do not be afraid. And Peter answered Him and said, “Lord, if it is You, command me to come to You on the water.” So He said, “Come.” And when Peter had come down out of the boat, he walked on the water to go to Jesus. But when he saw that the wind was boisterous, he was afraid; and beginning to sink he cried out, saying, Lord, save me! And immediately Jesus stretched out His hand and caught him, and said to him, O you of little faith, why did you doubt? And when they got into the boat, the wind ceased. Then those who were in the boat came and worshiped Him, saying, Truly You are the Son of God - Matthew 14:27-33

What kind of Acknowledgement you have? 

Come to Jesus Christ with full Acknowledgement that He is God.