The number seven is said to be the holy number of God. The number seven is used over 700 times in the Bible. 54 of those are in Revelation. Many believe the number seven symbolizes spiritual perfection and that all existence is hinged on this number. There is certainly some interesting information circling the number seven, however the number in itself holds no supernatural power.
In Revelation, the seventh angel sounding his trumpet brings the accomplishment of the mystery of God. Similarly in Genesis, the seventh day marks the completeness of creation. There are too many of these accounts to go over in a blog post, and there is no need to. We can certainly draw application from the number seven, so long as the application is directly from the word of God. It is far too easy to idolize a number, to begin to think about how the number seven affects your life instead of how God would have you live.
Here is where seven becomes important. I’ll give you one account. Jesus said that we should forgive our brothers not “up to seven times, but up to seventy times seven” (Matt. 18.22 NAS). Since seven symbolizes completeness, we should not just forgive completely, but exponentially (70x) more than completely. This means that we should forgive infinitely. Interestingly, that is how God forgives, infinitely. There is no sin so heinous that he refuses to forgive (there is one that prevents us from seeking forgiveness, blasphemy of the Holy Spirit). There is also no number of sins that cuts us off from forgiveness, so it is infinite in both respects.
Taking from this example, I would employ you to simply use the knowledge of biblical number simply for study purposes and within reason. To run out and buy a number 7 Bible cover is not a sin in itself; just remember who you worship.