Philippians 2:12–13:

Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure.

John Murray, Redemption Accomplished and Applied (Eerdmans, 1955), pp. 148-149:

God’s working in us is not suspended because we work, nor our working suspended because God works. Neither is the relation strictly one of co-operation as if God did his part and we did ours so that the conjunction or coordination of both produced the required result.

God works in us and we also work. But the relation is that because God works we work. All working out of salvation on our part is the effect of God’s working in us, not the willing to the exclusion of the doing and not the doing to the exclusion of the willing, but both the willing and the doing…. The more persistently active we are in working, the more persuaded we may be that all the energizing grace and power is of God.

Greg Beale, A New Testament Biblical Theology, as quoted in the pre-pub manuscript:

True saints should be psychologically motivated to fulfill God’s precepts because they know that God has given them the power to do so. … This kind of motivation is comparable to my neighbor’s desire to remove snow from his driveway. He has a fine snow-blower and gets his driveway cleaned off quickly. On the other hand, I do not own a snow-blower but have only a rusty snow shovel. When it snows a few inches, I have no desire to go out and shovel the snow. After it keeps on snowing and I still don’t go out to clear it off, my wife gives me a polite implied command by way of questioning, ‘when are you going to shovel the driveway?’ But I have no desire to respond positively to her command. I continue to let the snow build up until after the snow has finished falling, and then I go out rather reluctantly to shovel. I don’t have the motivation to clear off the snow because I don’t have the power to do it effectively. On the other hand, my neighbor has all the desire in the world because he has the power to remove the snow effectively. When one has the power to do something, the motivation for doing it follows.