It requires all the care and faithfulness which we can exercise in order to keep the faith of the Lord Jesus for there are invisible agencies around us in sufficient numbers to encourage the slightest disposition they may discover in us to forsake the true way, and fan into a flame the slightest spark of discontent and unbelief. [These] spirits are watching us continually for an opportunity to influence us to do evil or to make us decline in the performance of our duties.
President Brigham Young, Journal of Discourses, Vol 12:128
Imagine this, there are about 100 billion spirits that were before we all came to earth. Out of those 100 billion, a third was removed from heaven to become devils, angels to the devil.
So, that's about 35 billion evil spirits that are on this earth right now. Now, that's about 5 spirits per person based on population alone. But....the devil cannot tempt or even surround children. So, subtract those spirits from the children and add them to the older kids and adults.
And again, those that are wicked people on this earth don't need as many spirits trying to bring them down because they're already down. So, that means the righteous have even more spirits trying to deceive them and make them fall. Therefore, depending on a person's righteousness, a person may have multitudes of evil spirits surrounding them at one time.
And their only purpose is to make us deny the truth, to make us fall flat on our faces. They do this 24 hours each and every day. They are constantly whispering lies and deception, sometimes yelling it. They wait until they get an opportunity and then they attack but they are constantly surrounding us until that opportunity.