Paul said that the Philippians should always be obedient as they work out their salvation in fear and trembling, since God worked in them. There should be no arguing or murmuring, so that they would be innocent children of God, shining like stars in the world among a perverse generation. Then Paul could boast about them on the day of the Lord that he had not labored in vain. Instead, he would rejoice with them. Thus, together they both would be glad.