They profess to know God, but they deny him by their works. They are detestable, disobedient, unfit for any good work. (Titus 1:16 ESV)
There are those who make much noise about their own righteousness. They are loud and brash with their opinions for or against this thing or that, making sure that we all know how deeply they hold their Faith. But Christian faith isn't simply a matter of belief. Yes, salvation is by faith alone, sola fide, as Paul makes crystal clear in his letter to the Romans. Yet, the tendency toward extremism is held in check by the word of James in 2.26 "For as the body apart from the spirit is dead, so also faith apart from works is dead."
Often scholars pit one Apostle against the other but here in the letter toTitus Paul clarifies the same teaching. Works betray the reality of ones faith. Put another way, saving faith has demonstrative acts that accompany that belief. The longer one walks with God the more our own insubordination and rebellion should subside into submission to the formative hand of God's Word. When we persist in our own ways we make ourselves useless for the King and his purposes.
The unusable Christian is most frustrated. Each challenging word from the pulpit does not fall upon good soil; every effort to do something of significance ends in futility; every step forward in growth is undermined by the shallow faith that cannot yield to the Lord. We must die daily to self. We MUST learn to submit to God. We do this excruciating work as an honor to God. If we don't we remain unusable.