What does your faith mean to you? Is it something you barely acknowledge in your daily life, or is it actually something more? As Christians, we are told that faith without works is dead. Faith is more than just intellectual assent: It requires dedication.
Jesus gives an excellent analogy in Matthew 7, where He describes the difference between a wise and a foolish man. The wise man builds his house on a solid foundation, and so his house survives a storm. The foolish man builds on sand, and his house collapses at the slightest hint of trouble.
Now here's the scary part. There is an ominous "therefore" to account for. What is that "therefore" there for? It is simply there this: Not three verses earlier, Jesus tells of people who, when they come before Him on Judgement Day, boasted of their good works. They prophesied in His name, they drove out demons in His name, they did miracles in His name. Unbelievers are definitely building on sand, but what are we building on as Christians? Even we can build on a bad foundation.
Perhaps you're suddenly feeling a bit uncomfortable right now. If we can live Godly lives, call Jesus Lord on Judgement Day, and still be told we are workers of lawlessness, what can possibly be done? The emphasis is on "these words of mine". If we hear and act on them, we are like the wise man. But Jesus' words boil down to this: "You're not good enough, so rely on me instead."
There is not a man on this Earth who has anything God wants. You can't pay Him. You can't feed Him. You can't clothe Him. You can't shelter Him. Even what you give to Him, He gave to you first. And you ultimately defiled it all. But because Jesus took the penalty for all of that, your works become pleasing to Him. It all comes down to that. Who are you relying on? Are you trying to boast of your own goodness, or trusting in God's? If in yours, you're on as shaky a foundation as those who never knew Him. If in God's, you will lead a productive life, and continue into eternity.