Our Scripture reading today is Hebrews 3:12-15.
Verse 13, "But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin."
Beware of the deceitfulness of sin.  The longer we are involved, the more deceitful it becomes.  The longer we yield to the temptation, the easier it is to continue yielding.  This is when the hardening takes place.  Our continuing in sin will eventually quench the Holy Spirit. (1 Thessalonians 5:19, "Quench not the Spirit.")  We will begin to hear less and less and of his voice.  When this happens, it only compounds the situation we are in even more.  God's Spirit is our much needed guide.
We are challenged in the beginning of verse 13 to exhort one another.  This exhortation starts with ourselves and then to others we are influencing.  Our faith must continue to be strengthened so that we able to encourage others to do the same.  Also, I am to be willing to accept this encouragement.  Be thankful for faithful brothers and sisters in Christ that are living a Godly example and are will to encourage you to do the same.