Is this a contradiction?   No.   

Prayer is to prepare.   

Scripture records very few instances where Jesus prayerd during His interaction with people.   
When Jesus prayed, it was to prepare Himself for the work that He did with the people.   

Now when all the people were baptized, it came to pass, that Jesus also being baptized, and praying, the heaven was opened, Luk 3:21 Jesus underwent purification (baptism) but He had no need of it.     Mat 3:15 Jesus prayed to His Holy Spirit, His Father.      Jesus connected His Soul with His Spirit.      When we pray we connect our soul with our New Spirit which is born of the Holy Spirit.     Our New Spirit is one with the Holy Spirit Joh 17:11,22.

Then they took away the stone from the place where the dead was laid.     And Jesus lifted up his eyes, and said, Father, I thank you that you have heard me. Joh 11:41 Jesus thanked His Holy Spirit Father for answering the prayer before the manifestation.      Jesus' soul was in complete agreement with His Holy Spirit.     It is for this reason that He was able to speak the Truth, to heal, to deliver and to do the miraculous.      When we receive the Mind Of Christ our soul comes into agreement with our New Spirit which is one with Christ's Holy Spirit.      The supernatural becomes the norm in such relationship.

And I knew that you hear me always: but because of the people which stand by I said it, that they may believe that you have sent me. Joh 11:42 Jesus is saying that His Holy Spirit hears His heart and responds with no words being spoken.     What Jesus said aloud was to acknowledge the Holy Spirit before the people.      Just as with Jesus, the Holy Spirit hears us before we ask in the sense that He has already made provision.      Our prologue and epilogue should be thanksgiving and praise.

Ask, and it shall be given you; seek, and you shall find; knock, and it shall be opened unto you: Mat 7:7 Jesus is teaching about faith.     To ask effectively you must speak what you desire and you must believe that you will receive.      When we seek we must seek in faith so that we will recognize what we are seeking when we see it.      When we knock we must expect the door to be opened and we must be prepared to enter in confidence.

Pray without ceasing. 1Th 5:17 We ought to walk in awareness of the Holy Spirit in us such that all our thoughts are shared with Him and processed in accordance with His Word.      In so doing, we pray without ceasing.

And when he had sent the multitudes away, he went up into a mountain apart to pray: and when the evening was come, he was there alone. Mat 14:23 prayer is communing and fellowshipping with the Lord.      Jesus needed refreshing and so He spent time communing and fellowshipping with the Lord.      Upon spending time with the Father, He was prepared to deal with the issues that He would face the next day.

And Jesus said unto them, Because of your unbelief: for truly I say unto you, If you have faith as a grain of mustard seed, you shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you. Mat 17:20 Unbelief undermines faith and blocks the blessing from arriving.      It is not the quantity of faith that is important, it is the quality.     unbelief pollutes faith.      Pure faith in the absence of unbelief is capable of moving mountains.

Then he answered and spoke unto me, saying, This is the word of the Lord unto Zerubbabel, saying, Not by might, nor by power, but by my spirit, says the Lord of hosts. Zec 4:6 The Holy Spirit is the Power of God.      In the Creation, God Spoke and the Holy Spirit moved to effect His Words.     Gen 1:2

And Jesus answering says unto them, Have Holy Spirit Faith. Mar 11:22 The disciples were amazed at the withered fig tree and wanted to know how Jesus did this to the tree.      Jesus answers them very succinctly by telling them to believe with Holy Spirit faith.      Jesus did not come to show off and then leave us in awe.     He came to:    → clean us up    → teach us    → empower us    → to be like Him.      Jesus is telling us to operate in the supernatural faith of His Holy Spirit.      Note: The word 'in' is not in the original Greek phrase which the KJV translates as 'Have faith in God'.     It should have read 'Have God faith' or 'Have the faith of God' rather than 'faith in God'.      Since we know that God is Spirit (making Him the Holy Spirit of Christ Jesus), this phrase should best be rendered as 'Have Holy Spirit faith'.      Remember, Faith is one of the Spirit Fruit.      Unfortunately, this is another example of how the ' God being' was given an existence separate from the Word and Holy Spirit as a result of the translators' trinitarian concept of the Creator.      Jesus goes on in this passage to tell His disciples to just speak (word) and believe ( Holy Spirit faith) and their desires would be met.     There is no indication that some other being is involved in the process.      Even, the 'when you pray' statement of Mar 11:24 is misunderstood to reference a ' God being' when Jesus instructed us to pray to our Heavenly Father who is His Holy Spirit.

And all things, whatsoever you shall ask in prayer, believing, you shall receive. Mat 21:22 ask, believe and receive is the simple, powerful protocol that Jesus instituted for us.

You ask, and receive not, because you ask amiss, that you may consume it upon your lusts. Jam 4:3 Carnal Minded believers will likely be petty and selfish in their requests.

And the prayer of faith shall save the sick, and the Lord shall raise him up; and if he have committed sins, they shall be forgiven him. Jam 5:15 Asking is necessary Mat 7:8.      Believing is critical Mar 11:24.      When we ask in faith we receive Mar 11:24.      For the sick to be saved is for them to be made whole.      Sickness and sin are closely connected.     When a person comes to Christ Jesus in faith they are made whole - in their Spirit Soul And Body.

Confess your faults one to another, and pray one for another, that you may be healed.     The effectual fervent prayer of a righteous man avails much. Jam 5:16 Effectual prayer is prayer that produces results.     Results come from speaking in faith.      Fervent prayer is prayer that issues from your Heart Faith, from a place of compassion and earnestness.      We are instructed here to pray one for another.     This is speaking about the body of Christ and members praying for other members.      We are not to pray for unbelievers without first presenting the healer to them.     We are to witness to unbelievers so that they become believers and then we pray for their other needs.      If a person rejects Christ Jesus they are to suffer the consequences of their sin.     Don't ask the Lord to violate His Word.      remember, it was Jesus' teaching that produced faith for the healings that followed.      In the first part of this verse James is not talking about airing dirty laundry.      We are to confess our offense to the person we offended.

And he spoke a parable unto them to this end, that men ought always to pray, and not to faint; Luk 18:1 praying in the Spirit.

Pray without ceasing. 1Th 5:17 We ought to walk in awareness of the Holy Spirit in us such that all our thoughts are shared with Him and processed in accordance with His Word.      In so doing, we pray without ceasing.

Continue in prayer, and watch in the same with thanksgiving; Col 4:2 praying, watching and thanking is the model for our lives.

Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto the Lord. Phi 4:6 Don't worry.     Be happy in the confidence that prayers given with thanksgiving and faith will be rewarded with the blessing that is requested.      Some Believers do not believe it is the Lord's will to give us the desires of our hearts.     They believe this despite what Jesus said in Mar 11:24.      Remember that Satan is a thief and a liar.     He steals the promises of the Lord by getting you to doubt what the Lord has said.      Resist the devil and have faith in the Lord!     Mar 11:22