"Now the just shall live by faith: but if any man draw back, my soul shall have no pleasure in him.
But we are not of them who draw back unto perdition; but of them that believe to the saving of the soul."
Consistency in faith isn't always easy. Peter faltered as he was walking on the water, and sometimes we falter too, in accomplishing things in our lives that are at least close to equally difficult. :) In Christ's parable of the sower and also in Lehi's dream we see that some people reject the gospel entirely, but so often we accept it at first, but then harden our hearts or become caught up in other things... or wander off into forbidden paths.
I had a roommate in college who thought that she had been a "fence-sitter" during the war in heaven. And we too often try to fence-sit when it comes to doctrines or tasks that are hard for us. The thing is, I don't think it was possible to be a fence-sitter in the war in heaven... and I don't think that it is something that, even now, we can do for very long. Eventually we're going to cross the fence into God's yard, or we're going to retreat to perdition, which first of all isn't going to be very fun, and second of all... doesn't it hurt to sit on the fence like that?
I think that sometimes the hardest thing to have faith in is ourselves. Faith that we're going to make the effort necessary to change. Faith that there is anything in there worth saving sometimes. ...But God is there for us even then. He offers to change our hearts. He blesses us with motivation and power. He is there to lift us up when we fall. There are so many justifications that we can think of for giving up or for not staying with God. For going halfway and then retreating. We could talk for days about them. But this scripture tells us "we are not of them who draw back." ... Today, instead of doubting ourselves and doubting God's ability to make us equal to the task... let's try having faith in this one statement. We are not of them who draw back. WE are of them that believe, unto the saving of the soul. Let's act like it, and get off that painful fence and start moving forward. :)