Unlike either of the other Synoptic Gospels, Luke has sought to express the humanity of Christ in the portrayal of His life, as opposed to his Kingship in Matthew, and His servanthood in Mark. Luke has sought to achieve this by emphasising the prayer life of Jesus, and as a result, there are seven accounts of Jesus praying which are peculiar to Luke. The NT concept of prayer is "the uplifting of the heart to God with whatever motive", a form of worship encompassing "all attitudes of the human spirit". It is perhaps most simply defined as "communion with God." What is signified therefore, is that though Jesus is God, in His incarnate state He is entirely dependent upon His Father in order to fulfil God's purpose for His life. Moreover, Jesus as the perfect man 'needed' to pray, how much more do we, in our imperfection?
What becomes apparent in examining Jesus at prayer is how personal our communication with God is. In the four recorded prayers of Jesus the relationship aspect of prayer is expressed as Jesus addresses God as Father: for example in Luke 10:21 "Jesus, full of joy, through the Holy Spirit said, 'I praise you Father, Lord of heaven and earth'." (Also Luke 11:2 & 23:46 & 34). Not only were these prayers personal, they were often conducted in private or at least away from the crowds, with only a number of the disciples present. Luke 5:16 reads "But Jesus often withdrew to lonely places and prayed" and Luke 9:18 from the KJV says "as he was praying". The result of His regular fellowship with God was the strengthening of His relationship with His Father until Jesus could say in John 10:50 "I and the Father are one" (cf. John 14:9 & 10), and this close communion was maintained because Jesus' life was totally consecrated to God. As Jesus expressed Himself in John 6:38 "For I have come down from heaven not to do my will but the will of him who sent me". This is also reaffirmed in the Garden of Gethsemane, when Jesus is preparing to confront the cross, where he prays "Father, if you are willing take this cup from me; yet not my will, but yours be done." (Luke 22:42).
As Jesus was in complete submission to His Father's will, he was reliant upon His Father to reveal His plan to Him. This dependence upon God demonstrates the humanity of Jesus and significantly, many of the references to Jesus praying are just before major events in His life. In Luke 3:21 Jesus emerges from the water, at His baptism, praying and is endued with power by the Holy Spirit to commence His ministry. In Luke 6:12 Jesus spends the whole night in prayer before He chooses the Twelve to be His disciples. In Luke 9:28 Jesus is transfigured, whilst praying before Peter, James and John. As we have seen already, Jesus prays in preparation for the cross, in Gethsemane and on the cross staring death in the face. Luke 23:46 records the completion of His human ministry: "Father, into your hands I commit my spirit" (See also Luke 5:16; 9:18; 10:21 & 11:1).
The success of Jesus' ministry, through His prayer life, prompted the disciples' request that He should teach them how to pray. Jesus introduces the subject with a prayer meant for general use, which although called the 'Lord's Prayer' might more aptly be named the 'disciple's Prayer' (cf. Matt. 6:9-13). Jesus then taught about attitudes in prayer, which consisted of three parables found in Luke 11:5-8; 18:1-8 & 18:9-14. The first teaches that although God is always willing to give to His children there are times when we must persist shamelessly in our supplications. The second parable is in the same vein as the first, teaching that although answers to prayer may not be immediately forthcoming we are to faithfully persist and not lose heart. The third and last parable teaches that we are always to approach God in humility, recognising that it is only what we are in Christ that makes us acceptable and not what we are ourselves.
Although most of the teaching on prayer, that Luke has recorded, was in the form of parables (as related above). Jesus also taught His disciples by example. The example he gave was that we are to live a 'life of prayer', therefore he exhorted His disciples to pray. In Luke 22:40 & 46 the disciples are instructed by Jesus to "Pray that you will not fall into temptation". In Luke 10:2 they are told to pray for workers for the Kingdom of God and in Luke 6:28 to "pray for those who ill-treat" them. Similarly we see the prayer of intercession in the ministry of Jesus when He prays for Peter in Luke 22:31 and His enemies, whilst on the cross, in Luke 23:34. A 'life of prayer' therefore extends the boundary of prayer from the personal to the corporate level, where we are not only to pray for each other, but to unite in prayer. These views are expressed by Luke in the opening and closing chapters of his Gospel where a body of believers are seen praising God in prayer (Luke 1:10 & 24:53). But Jesus issues a warning about individual prayer in such a gathering, that the prayers are kept succinct in order that we don't become pious (Luke 20:47).
In his Gospel Luke has tried to impress upon the reader the importance of prayer by demonstrating the attitude of Jesus to prayer and the frequency with which He prayed. What we see is that Jesus, as the expression of perfect humanity, lived a life totally surrendered to the 'purposes' of His Father and was only effective in His ministry because He sought the will of God in all the areas of His life. Likewise, the Christian life is to be a life of prayer, founded upon the Father-Son relationship that God has established through Christ. We are to trust him in the assurance that he will provide the answer to all our supplications because our lives are submitted to Him in complete obedience and our approach to God should be one of reverential fear to guard against the complacency of such informality could breed.
 J. Hastings, ed. Dictionary of the Bible. Edinburgh: T.& T. Clark, 1958, pp.744, 747.
 J.D. Douglas, organising ed. New Bible Dictionary, 2nd edn. Leicester: IVP, 1988, p.958.
 F. Grant, & H.H. Rowley, Dictionary of the Bible, 2nd edn. 786-789.