I imagine most Christians struggle with belief at some point in their lives.
Doubts, fears, dissapointment with God.
If you are like me you have friends who struggle.
Have you ever warned them about that, exhorted, encouraged them to believe?

Heb 3
12See to it, brothers, that none of you has a sinful, unbelieving heart that turns away from the living God. 13But encourage one another daily, as long as it is called Today, so that none of you may be hardened by sin's deceitfulness.

It appears from this passage that if our fellow Christian is starting to doubt, we have to encourage them to stop doubting. Thats unusual, especially in this day and age when we encourage each other to journey together. Its almost non PC of the Bible.
We are to see to it...... That sounds a lot like confrontation to me. Confrontation is not something I like, at all. And generally I am a good listerner (I hope), and are rarely presciptive. But there must come a time when my friend needs a good kick, stop doubting, start believeing, and get on with it. (in love of course) :)