Luke 22:31, 32 (NKJV)
The Bible is very clear about the fact that we have an enemy, the devil. The Bible tells us in 1 Peter 5:8 that "the devil walks about like a roaring lion, seeking whom he may devour"; the devil is actively seeking people to attack. There are some different methods that he will use to try to attack us but his goal is always the same, to separate us from God and His Word. If the devil can separate us from these things we are going to be easy prey for deception and destruction. The good news is that Jesus has already defeated the devil and we can do something about the devil's tactics.
In Luke 22 Jesus was celebrating the Passover with His disciples. Jesus began to explain how He was going to be betrayed and put to death. He also said something very interesting to Peter that we can learn an important lesson from. Jesus told Peter that Satan desired to "sift him as wheat". This is referring to the process of separating the wheat from the chaff by shaking it. This is a picture of what the devil tries to do in the lives of believers today; the devil wants to shake people loose from their connection to God, His Word, their local church, and other believers.
Many Christians, especially when they are "young" believers, do not yet have a solid foundation in God's Word and they are easily shaken by trials, temptations, offense, and problems. Just like a child in the natural needs support from their older siblings and adults so do spiritual children. Just like Jesus did with Peter, we need to pray for the stability of believers and support them with our prayers. We can pray that God would help these believers to keep the truth in mind and not yield to the pressure they may be facing. Through our prayers we can help believers to be stable and strong in the face of temptations, tests, and trials. Jesus did it for Peter and we can do it too.