Praying in secret and the Lord’s Prayer.
v.5-6 Just as we have seen with giving to the needy, (public) prayer can become perverted when there is an internal corrupt motive. Here hypocrites are described by Jesus as praying in church or in public to be seen by others. Praise by men is all the reward they will ever get. While public prayer has value, praying in private, in your inner room, allows you to focus more exclusively on God. Then God, who sees what you do in secret, and will repay you. As an example, Jesus prayed alone early in the morning (Mk 1:35) and on a mountain (alone) at night (Lk 6:12).
v.7-8 Jesus tells us to not pray as the heathen with vain repetition and many words. The Father knows what we need before we ask. A repeated prayer is not vain repetition. Vain repetition is a babbling of words (long winded, flowery oration) without a sincere desire to seek God’s will. Jesus told a parable that indicated a sincere repeated request is permissible (Lk 18:1-8). Jesus would value quality in prayer (the attitude of faith that underlies it) rather than quantity (frequency or number of words).
v.9 V. 9-13 are the ‘Lord’s Prayer.’ Perhaps more rightly the “disciples prayer’ since it is a model for their prayers. He starts with ‘Our Father.’ The image of God as our father brings to mind both his authority and his loving kindness. ‘In heaven‘ speaks to God’s sovereignty. ‘Hallowed…‘ indicates we are to start our prayers by holding God in reverence and honor on earth as he already is in heaven. We should not address God causally or flippantly — he is holy, all powerful, all wise and perfect. God’s ‘name‘ is a reflection of who he is as he has revealed himself. The prayer expresses the desire that his name not be despised by those he created in his image. (Recall the first three commandments, Ex 20:3-7.)
v.10 Christians are to pray for the establishment of God’s kingdom here on earth. ‘Your kingdom come.’ That is, the consummation of God’s purposes on earth. This would include not only the future coming of Christ, but also the advancement of the kingdom by Jesus’ disciples now through word and deed. ‘Your will be done.’ This request asks that God’s will, and not our rebellion and sin, prevail in our lives and on earth. ‘On earth as it is in heaven.’ This phrase applies to the three previous requests (your name, your kingdom, your will).
v.11 This verse is the first of three petitions for the disciples needs. ‘Our daily bread’ means the physical needs that are necessary for today. Christians should pray each day for today’s (or tomorrow’s) essentials for life (see also Prv 30:8). We should request that which we need and not things that are based on our greed (Jas 4:3). Below in v.25-26 Jesus tells us to not worry about the needs of today (having placed our trust in God).
v.12 We are each indebted to God because of sin. This petition requests forgiveness of those debts as we also have forgiven those indebted to us. As v.14-15 below indicate, our forgiveness from God and reconciliation of our relationship with God is predicated on our forgiving our fellow man who has sinned against us. It can perhaps be said that only a repentant heart can show forgiveness to others.
v.13 While God himself does not tempt us to do evil (Jas 1:13), he may allow circumstances in which we are tempted (i.e., testing our faith). The phrase is a request for God’s protection from sin (and evil).
For yours is the kingdom and the power and the glory, forever. Amen
v.14-15 These versus comment on the petition in v.12 (see comments there). In the parable of the unforgiving servant (18:21-35) the Lord asks, ‘I forgave you all that debt, shouldn’t you also have forgiven your fellow?’

Read Matthew 6:5-15