There is a very real danger of confusing faithfulness with faith. The danger is we can have all the outward trappings of godliness (2 Tim. 3:5) while not actually having God. Such a situation would make faithfulness an idol. The key is to realize that faithfulness is the process, not the product.
Doing things like regular church attendance, having regular prayer and Bible study times, and avoiding sin in all forms are of course things we ought to strive for. But they are not the goals. The goal is to be in relationship with God regardless of life circumstance. That is called faith.
Ironically if we are not careful the things we do to stay in relationship can end up being substitutes for the real thing. If we were to measure our faith by things like how often we do daily devotions or how pious our behavior is we are building houses on sand, because we often fail to meet the lofty goals we set for ourselves (Matt. 7-26-27). A better measurement is commitment to our relationship with God and having our lives reflect that commitment as often as possible.
How surrendered are we to living the way of life that God has called us to? For instance, I may not be faithful to loving my neighbor 100% of the time, but I am committed to it. I may not faithfully make it to worship service 100% of the time, but I am committed to those who I share life with in my local community of believers. And I may not be faithful to spending money totally how God would want me, but I am committed to being a generous Christian and practice it the best way I know how in my fallen state as a human being.
Of course we don’t want to use our failures as an excuse to be average. If we have no love for church membership, show no remorse for committing “little” or “big” sins, become lax in practicing spiritual disciplines, and actually delude ourselves into thinking that any money that comes into our possession actually belongs to us (instead of God) —those within our sphere of influence may wonder whether we are Christ followers at all. So we can’t have faith without faithfulness.
But there is no question that relational faith is what will determine the quality of our faithfulness.