In Philippians 2:12, we are told to work out our own salvation with fear and trembling. But verse 13 says “for it is God worketh in you both to will and to do of his good pleasure.” I have never, to my knowledge, heard verse 13 quoted before. It seems most stop at verse 12. When I read verse 13, I was unsure of what it meant to verse 12. Why would we need to work out our salvation with fear and trembling when God is working in us according to verse 13?
After talking about the fact that Jesus has been given all authority by the Father, Paul states:
"So then, my beloved, just as you have always obeyed, not as in my presence only, but now much more in my absence, work out your salvation with fear and trembling; for it is God who is at work in you, both to will and to work for His good pleasure" (Philippians 2:12-13).
It is God's purpose to save mankind and His plan was to do so through Jesus (Ephesians 1:7-12). God's purpose was established from eternity. "This was in accordance with the eternal purpose which He carried out in Christ Jesus our Lord, in whom we have boldness and confident access through faith in Him" (Philippians 3:11-12). However, this does not mean that God did not plan for men to have a role in their salvation. One requirement God has of men is to fear and obey Him. "The conclusion, when all has been heard, is: fear God and keep His commandments, because this applies to every person" (Ecclesiastes 12:13). It is by the fear of God that we reach life. "The fear of the LORD leads to life, so that one may sleep satisfied, untouched by evil" (Proverbs 19:23). Thus, Paul states that we must always obey God with fear and trembling because we understand that there will be no excuses when we appear before the judgment seat of Christ. "For we must all appear before the judgment seat of Christ, so that each one may be recompensed for his deeds in the body, according to what he has done, whether good or bad. Therefore, knowing the fear of the Lord, we persuade men" (II Corinthians 5:10-11).
My efforts can never earn salvation for me, but if I do not obey God, I can keep myself from being saved. The works required of me are not of my own devising, but they are the works God prepared and demands of me. "For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them" (Ephesians 2:10). God has prepared works in advance that He expects of us to do -- not works that earn salvation, but good works that serve the will of God.
God, through His teachings, shapes us to be instruments of His purpose.
"In the exercise of His will He brought us forth by the word of truth, so that we would be a kind of first fruits among His creatures" (James 1:18).
"Now the God of peace, who brought up from the dead the great Shepherd of the sheep through the blood of the eternal covenant, even Jesus our Lord, equip you in every good thing to do His will, working in us that which is pleasing in His sight, through Jesus Christ, to whom be the glory forever and ever. Amen" (Hebrews 13:20-21).
Paul states that it is not just outward obedience but an alignment of our will with the will of God. We obey because we desire to please our Lord and King.