The Command is Twofold
First, to “work” is “to will and to do,” and that is true of all work, even of the most routine kind. It is always the result of a decision being put into effect even if it is made relatively unconsciously. Life is divided into thought and action, whether of word or deed. It is not mindless but involves motivation.
Second, two different words for “work” are used, and that is indicated somewhat by the prepositions “out” and “in” that follow the verb “work” in our translations. It is important to realize that the distinction between them does not lie between the visible and the invisible but between activity (v. 12) and energy (v. 13).
Third, two parts to the duty are connected by the preposition “for,” and while they should be distinguished, they should not be divided. They bring together law and grace. How should the parts be described? As a condition and promise? No. If they were, the sense would be “You obey and God will help you,” which leaves the believer defeated and bereft. The first part is a command or gospel exhortation. What is the second? It is an explanation—one that is immensely encouraging. The exhortation tells everyone what they are to do, and the explanation declares that they are not alone in doing it. The word order in verse 13 is unusual—the opening word is “God,” which assures the “working” believer that his “willing” and his “doing” are divinely energized and brought to completion.
So, how does the Christian comply with this command? It is not by thinking in percentage terms or by alternating phases of action. Such apportioning is destructive of the remarkable combination that is present in this declaration, which amounts to God’s being active in the believer and the believer’s being active in God. Such a union is only possible because God, as Creator and Regenerator of human beings, indwells them as their Sanctifier. As the believer is brought into communion with the Father through the Son and by the Holy Spirit, such interpersonal activity becomes a reality. This is the very center of the gospel mystery of sanctification.
A circle of cooperation is therefore set up in which concurrent and cooperative “willing and doing” become a mysterious and deepening reality. Private and public, individual and corporate, study and service, praise and prayer, worship and witness, meditation and the means of grace all cohere, intensifying reverent submission (“fear and trembling”) with a view to pleasing God (“his good pleasure”) according to His mind and will.
This pathway, however, is not easy to tread. There is the flesh and the fiend to contend with, but it is the highway of grace to glory. There will be many falls on it but none out of it. But willing and working according to God’s Word means that He is energizing and will enable and complete what He has begun on the day of Christ.