A wise priest I know once said, “Doesn’t having faith simply mean being faithful?”
But what does it mean to be faithful?
Does it mean to verbally proclaim a faith in God? Follow a set of rules? And if so, which statutes does one follow? Or does being faithful simply imply one should be nice to everyone?
Or does it mean to persevere, hoping something better will be around the corner if one just hangs on a little bit longer?

To love much is to suffer much
For the Christian, being faithful is the proof of love. It is the sign of love’s authenticity. He understands well that to love much he must suffer much, but he undertakes it anyway.
Why?
Because love is not passive; it requires one to remain faithful, and this can be painful at times.

It is said love is the most powerful force on earth because it is able to conquer even death.
How does it do this?
By making up for those who don’t love and sorrowing on their behalf, thereby cooperating with God to give life to their souls.
Why would one do this?
Authentic love is willing to undergo much suffering for the sake of its beloved.
That means, the more one loves, the more one is affected when his beloved is suffering, undergoing trials, or even languishing from his own sinful conduct.
And the more one loves in this way, his capacity for love grows, even to the point of praying for those who hate him. This kind of love is impossible without the help of God (Matt 19:26).
That brings us to the question: Who would hate someone so good?
If they hate Me, they will hate you
Jesus, the Founder of Christianity, loved so much that He willingly took on everyone’s suffering onto Himself.
But just before He died He promised His disciples and everyone who follows Him afterwards, “If the world hates you, be aware that it hated me before it hated you” (John 15:18).
Love and suffering go hand-in-hand. Metaphorically, they are two sides of the same coin.

But it is a cleansing suffering–one that is vastly different from suffering for doing wrong, which feeds feelings of alienation and intense isolation.
God suffers?
The world demands everyone to be faithful to its statutes, which directly oppose those of Christianity.
Since Jesus is also God and therefore, outside of time, He lives in the “now.”
Therefore, one can conclude that in His divinity, Jesus still suffers (Acts 9:4).
So when one suffers for doing what’s right, God suffers with and in him as well, bringing a profound sense of peace.
It is a peace the world cannot give, so out of jealousy, envy, intolerance and greed, the good suffer for their acts of love, just as Christ did (and does).

A fundamental difference
The world hates authentic Christianity and those courageous enough to stay faithful to its teachings.
A fundamental difference between Christianity and all other world religions: The Christian is not faithful simply to a set of rules; he is faithful to a Person (or more precisely, three Persons in one).
How is he to live out a faithful life to God?
Jesus answers that question: Through loving one another as God loves us (entirely, unconditionally, unselfishly, without counting the cost).
How does one do this?
He told His disciples the answer to this very question (also at the Last Supper): “If you love Me, you will keep My commandments” (John 14:15).
These “commandments” are the Ten Commandments found in the Book of Exodus (20:1-17) dictated to Moses by God, and the eight Beatitudes dictated by Jesus to the crowd in His very first sermon in Matthew’s Gospel (5:1-11).
The Ten Commandments reflect one’s love for God, and the Beatitudes elevate the Ten Commandments to their intended perfection.
One thing every single statute has in common is they are all life-giving in some way: They either preserve, guard, or give life. Since God is the Author of life this makes perfect sense.

Therefore, the Christian proves his love for God not by utterances of faith but by being faithful to Him. He must show his faithfulness like anyone shows it in a marriage–by loving with all his heart, soul and mind (Matt 22:37).
And by loving others as God loves us (Mark 12:31). The Christian has the strength and courage to do this because he knows that God was (and is) faithful to him first.

“[God] in your great kindness, hear me, and rescue me with your faithful help” (Ps 69:13).