And immediately Jesus stretched forth his hand, and caught him, and said unto him, O you of little faith, wherefore did you doubt? Mat 14:31 Jesus saved Peter but at the same time explained why he sank.     Peter had a little faith and that was sufficient.     However, he also had doubt (unbelief).     His unbelief nullified his faith.

Jesus answered and said unto them, Truly I say unto you, If you have faith, and doubt not, you shall not only do this which is done to the fig tree, but also if you shall say unto this mountain, Be you removed, and be you cast into the sea; it shall be done. Mat 21:21 Jesus is speaking an `unbelievable` Truth.     He is telling us that the Lord has made faith available for us to do anything.

And when they saw him, they worshipped him: but some doubted. Mat 28:17 Notice that the disciples worshipped Jesus.     This is saying that they believed in Jesus as Creator.     Note also that Jesus did not prevent this worship.     This is an acknowledgement of His deity.      Some worshipped Jesus as Mighty God and some didn`t.     This will always be the case.     Some will believe while others doubt.     Since it is by Grace Through Faith In Christ Jesus that we receive His blessings, those who believe, receive, while those who doubt, go without.

For truly I say unto you, That whoever shall say unto this mountain, Be you removed, and be you cast into the sea; and shall not doubt in his heart, but shall believe that those things which he says shall come to pass; he shall have whatsoever he says. Mar 11:23 Faith is what Jesus will be looking for when He returns.     Faith pleases Him because He operates in it and wants us to as well.     It is divine faith - the Faith Of Christ Jesus.     It is how His power is released and how His will is accomplished.

Christianity is about an intimate personal relationship with the Holy Spirit of Christ Jesus who is the Creator of all things.   

The purpose of the Bible is to bring us to that relationship.   Those who by faith receive the Light and Truth of Christ Jesus will have all of eternity to get any specific questions answered.   

Those who need to know
   → how an internal combustion engine works,
   → how transmissions work,
   → how differentials work,
   → how steering mechanisms work,
   → how electrical systems work and
   → how brake system work
before they get into a car will be left behind.   

So it is with Christ Jesus.   You must receive Him by faith or be left behind.