Matthew 6:16
"Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward."
One of the groups whom Jesus consistently exposed were the Pharisees. The Pharisees were certainly very religious people who made sure everyone saw how good they were. If you were to come across a Pharisee today, you would think of them to be a very good and moral people. They attended their services regularly, tithed of all their income and they prayed on a daily basis. They were very good people if you compared them to other men.
On the other hand, Jesus was not at all pleased with their type of worship. They were a people who only performed moral acts so that they could be seen of man. When they gave their offerings, they made sure that everyone saw how much money they put into the offering plate. When they prayed, they prayed openly so that everyone could hear their "great" prayers. When they fasted, they would fast in such a manner that everyone knew they were fasting. Jesus said about this type of worship, "They have their reward." Their reward came from being seen of men.
Jesus desires a better type of worship from the Christian. He says in Matthew 6:1, "Take heed that ye do not your alms before men, to be seen of them: otherwise ye have no reward of your Father which is in heaven." Notice that Jesus wants us to obey Him, not for the recognition of man, but for the sake of doing right. This type of service to God produces an open reward.
Moreover, whenever you serve God not to be seen of man, then God has the opportunity to receive the glory by openly rewarding you. God wants to receive the glory in all that we do; however, when we do things openly to be seen of man, then there is no way He can get the glory. You must develop a mindset to serve God for one purpose, to please Him.
Let me encourage you to stop worrying about what others think of your Christianity and do it because it is right. The Devil loves it when the Christian is always concerned with what others think about what they have done. Preachers, stop worrying about how the sermon comes across and preach to please the God. Christian, stop being concerned with whether your soul-winning presentation is good enough and just go tell others about Jesus Christ. Furthermore, stop worrying about what others think of your prayers and just pray. One of the greatest days in your Christian life will be when you stop worrying about others opinions of how good you are doing and start serving God to please Him.
You have a choice every time you do something for God. You can serve God to be seen of man, and if you do this then you already have your reward. On the other hand, you can serve God out of complete obedience without being concerned with man's approval, and God will reward you openly. The greatest part about the latter type of service to God is that He receives the glory, will bless you openly and will also reward you when you get to Heaven. Don't have the type of Christianity that receives the immediate reward from man, but have the type of Christianity that simply does what it's supposed to do out of a desire to please God. This type of Christianity produces the greatest rewards that will last for an eternity.