Matthew chapter 6 (Sermon on the mount # 2)

Matthew 6: 1 is the theme for this chapter, and portion of the Sermon on the mount.
"Be careful not to do your 'acts of righteousness' before men, to be seen by them. If you do, you will have no reward from your Father in heaven."

Here Jesus is questioning the motives behind a Christian's "acts of righteousness". He is not telling us to neglect these things but rather to make sure we are doing them God and to glorify Him, and not simply to gain thanks, rewards, or approval from other people or to feel selfrighteous.

1. Hypocrites Beware: v. Hypocrisy is the act of pretending to have beliefs, virtues and feelings that one does not truly possess. The word derives from the late Latin hypocrisis and Greek hupokrisis both meaning play-acting or pretence. A classic example of a hypocritical act is to denounce another for carrying out some action whilst carrying out the same action oneself. In the three examples of Giving to the poor, Prayer, and Fasting the Hypocracy Jesus is warning His listeners of, is doing 'Christian' things not for the Glory of God, but for our own glory.
2. Rewards from God: Jesus says that God will reward what is done in secret. So the righteous things we do, while they should be hidden from others (in the sense of not seeking rewards for them) will not go unnoticed by God. However God will ignore the righteous things we do, IF they are done for the purpose of recognition and reward. It should also be noted that only doing righteous things so God will bless us is also a wrong motive. He will reward us if we do things which bring Him glory, and for the purpose of bringing Him glory.
3. Hidden does not really mean Hidden: Public righteousness, even when carried out in the knowledge that such acts will draw attention, is not wrong so long as we seek to be seen for God's glory rather than our own. Jesus here (I believe) is not saying we should only do His work in secret, but is illustrating how easy it is to justify our own desire to impress others as "being a light." We should do everything for God, and be concerned more with God's evaluation than with that of others. Many people practice religion without paying attention to God, and this warns us to search our motives.

Jesus then talks about storing up treasures in Heaven vs worrying about the wealth of the world. Jesus warns His listeners not to make material wealth our primary focus. "For where [our] treasure is, there [our] heart[s] will be also." Our focus should be on serving His kingdom and our eternal life with Him rather than how we can the most out of this life of the flesh. Jesus does not expect us all to be paupers but here He does tell us to be different from the accepted worldly and 'pagan' people around us. We are to seek Him and His plan for us, not the things of this world like money, fashion, fine foods, realestate investments, cars, boats, fine art collections, etc... Jesus says "seek first his kingdom and his righteousness, and all these things will be given to you as well." Notice that it does not say "all things" but rather "all these things". So what are the 'these things' He mentions? Food, Drink and Clothing. Not, wealth or status symbols but the bear essentials for sustaining life, not the comforts of an extravagant life. Jesus promises that if we first seek Him, He will provide the things essential for us to live. He may bless us with other material things, but they are not promised here, only the essentials.