The writer of the Hebrew letter says through inspiration in chapter 3, verses 12 -13:
12 Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God;
13 but exhort one another daily, while it is called "Today," lest any of you be hardened through the deceitfulness of sin.
The instruction to "exhort one another daily" is still a needed thing in our lives. We tend to "under-value" the good that a kind word of encouragement, a call, a text, or a short note can do in the lives of those around us. Never underestimate the good you can do for someone. You might have a part in "preventing an evil heart of unbelief" in a brother or sister.
Bro. Kevin Clark presented a lesson at the West Knoxville Church of Christ back in April 2011 and that lesson is now shared under the "sermons" section of our website. We would encourage you to take the time to listen to the lesson, so that you might be encouraged in this good work.