Summary: Faithfulness is not optional in our relationship with God, but is an integral part of our relationship with Him as it is with a marriage.
Pardon for sin and a peace that endureth Thine own dear presence to cheer and to guide;
Strength for today and bright hope for tomorrow, Blessings all mine, with ten thousand beside!
What does it mean to be faithful? Webster’s defines faithfulness as a person who is “firm in adherence to promises or in observance of duty”. It is a person who is “steadfast in affection or allegiance”. Faithfulness means to be trustworthy, true to your word and responsibilities, loyal and consistent.
PONDER THIS: If your car started 4 mornings out of 7 would you call it a faithful car. If your air conditioner cooled your house 3 out of 8 times would you call your air conditioner faithful? If you spouse only came home 2 nights a week, and they’re not a long distance truck driver, would you say they are faithful. If you only come to church, read your Bible, and pray on Sunday, DO YOU THINK GOD CALLS YOU FAITHFUL?
The word "faith" comes from the Greek word “PISTIS” and it means "trustworthiness”. The fruit of the spirit listed in Galatians 5 (quickview)  are aspects of Christ’s character in us, and are manifested in our behavior. Faithfulness, like each of the other fruit of the spirit, is built into our lives as we abide in Christ, and walk in the spirit rather than in the flesh. We live our lives to please God rather than living to please ourselves.
Faithfulness is not optional in our relationship with God, but is an integral part of our relationship with Him as it is with a marriage. In order for you marriage to work there must be faithfulness. Most people will not stay with a person that is not faithful to them. God is looking people who will consistently carry out His will. To be faithful is to be dependable, loyal, and stable.
There are two Hebrew words are often translated "faithfulness": emunah and emeth. The word “emunah” means "firmness, fidelity, steadfastness, and steadiness". The word “emeth” means “firmness, faithfulness, truth". Both of these words, in turn, come from the word aman, which means "to build up or support". This word conveys the idea of "firmness or certainty" and is the original source for our word “Amen”.
WHAT IS THE MOTIVATION BEHIND FAITHFULNESS?
Faithfulness is more than just attending church every time the doors are open. Faithfulness is more then singing in the choir. Faithfulness is not being part of a praise dance team. Those are all part of our show or manifestation of our faithfulness. However, there is a driving force behind faithfulness and until you understand that driving force you will never truly be faithful. The motivation that produces faithfulness is mutual respect and adoration. It is love. Because I love my wife and she loves me we made a commitment to each-other, before God, to forsake all others and be faithful to one another. Why, because of love. Because God loves us He has made a commitment to us and because He cannot lie, will keep that commitment to a thousand generations. Because you have a love for God you are faithful in serving Him. Because of love for God, I will bless His name. Because of love for God I go to church every time the doors are open, because He said in His word fail not to assemble yourself together and because I have love for Him and His people, I will be there regardless.