There is great joy in assurance. Paul tells the church in Philippi to live in obedience by working out their salvation with fear and trembling. If they are assured in their faith, they, like Paul in his time of suffering, will be able to rejoice in their time of suffering. Our assurance of salvation comes from the word of God. God promises that if we have trusted Jesus as our Savior than we have all that we need to be in perfect relationship with Him. There is nothing on earth or in heaven that will separate us from the love of God. This kind of assurance produces great joy in all circumstances of life.