Matthew 15.11 defines, it’s not what goes into your mouth that defiles you; you are defiled by the words that come out of your mouth.
The Muslims are wrapping up their holy week most characterized by fasting from sunup until sundown. Fasting has been used by religious people of all stripes from all time as a means to appease the gods and or garner their attention.
Christians have used fasting historically not so much for these purposes but to discipline the flesh so that we obey the Spirit.
It should seem odd to us that any real god can be so easily appeased by simply skipping meals. While the Muslims have been fasting they have also been killing one another even in their holiest of cities at the shrine of Mohammad in Medina.
When God lived among us He fasted. He fasted in preparation for war. He fasted so that He was spiritually fine tuned for His encounter with His enemy the devil who would try and appeal to His flesh in order to get Him to sin.
The devil used our common weaknesses to tempt God: self sufficiency (turning stones to bread), self importance (test God’s love by jumping off the temple) and self gratification (riches of the world). God Who is Spirit defeated His foe not by the flesh but by the Spirit putting to death the will of the flesh in order to obey the will of the Spirit.
Many people think they are good because they don’t do bad things. Most people have never murdered, committed adultery or stolen a large sum of money. In addition, many people have done some relative good. They have given a couple of dollars to the man on the corner. They have helped hold a door for the person behind them.
All of us however have thought murderous thoughts and spoken hateful words to another person. All of us have lusted in our hearts for other people or other things and have spoken such wishes to others. God is not impressed with our religious activity but with our heart’s purity. The One True God is not deceived by our few good deeds but looks into our hearts and hears our every word and knows our every thought.
This is why we need a Savior. We will never work our way to heaven before a God who measures such minutiae within us. He gauges us by Himself, since He is holy, perfect and absolutely good He requires us to be the same. Not possible for us who are born rebellious against God and at war with one another.
Fortunately, God came to earth to forgive us by dying for us taking the punishment from God the Father we deserved. We can be forgiven by God through the works of Jesus alone not by any religious activity we do ourselves.
Certain religious disciplines are good if they help us focus on God in order to obey God but in themselves they are worth nothing.