Let Him who Thinks He Stands Take Heed Lest He Fall
If we look at the context in this passage it is speaking to those who may think it's okay to live a lifestyle of sin and still be a child of God. So we see a caution within a command. "Let him who thinks he stands take heed lest he fall".
The caution is to those who think just because they profess to be Christians it entitles them to eternity and the inheritance that belongs to the saints of God. But Paul cautions them by showing them a practical example. The nation of Israel was saved from Egypt, they all were led under the same cloud, they all went through the same sea, they all drank from the same spiritual drink. Yet with most of them God was not well pleased. Why? Because they desired evil and chose evil over God.
The problem was that they thought it was all said and done when they left Egypt. When temptation came they were not ready; really, they were not even expecting it and when it came they fell hard. Even so, we must be careful to not be so arrogant as to think that salvation comes from a mere pray, or words that roll off a mans tongue. We must ask ourselves what is salvation?
Is salvation just merely a forgiveness of sin or a washing away of a sinful lifestyle? The Word of God says clearly that we are a new creation. We must now present ourselves and every part of our bodies, outward and inward, unto God for righteousness and holiness. We must not provide opportunity for the flesh, instead let us indulge on the things of God. Oh the audacity of one who may think it's okay to take what is Gods and use it for evil. You have been bought with the blood of Jesus, and you are now God's. Let us take heed from the fall and daily grow in a personal and loving relationship with our Lord and Savior Jesus Christ.