Every worldly Christian hinders the progress of the gospel--
Every member of a church who is living in secret sin,
who is tolerating in his heart any thing that he knows to be wrong,
who is not seeking eagerly his own personal sanctification,
is to that extent hindering the work of the Spirit of God.
For to the extent that we maintain known unholiness, we restrain the Spirit.
He cannot work by us as long as any conscious sin is tolerated.
It is not over breaking of commandments that I am now speaking of, brethren,
but I include 'worldliness' also--
a care for carnal things, and a carelessness about spiritual things;
having enough grace just to make us hope that you are a Christian,
but not enough to prove you are;
bearing a shriveled apple here and there on the topmost bough,
but not much fruit; this I mean, this 'partial barrenness'--
not complete enough to condemn,
yet complete enough to restrain the blessing,
this robs the treasure of the church, and hinders her progress.
- Spurgeon, "Travailing for Souls"