Sharing today from John MacArthur’s Grace to You blog.
by John MacArthur
Saving faith is a divine gift, not a human work. But that doesn’t mean true faith is passive or unaccompanied by good works.
The faith God graciously supplies produces both the volition and the ability to comply with His will (cf. Philippians 2:13: “God . . . is at work in you, both to will and to work for His good pleasure”). Thus faith is inseparable from obedience.
Louis Berkhof sees three elements to genuine faith: An intellectual element (notitia), which is “a positive recognition of the truth”; an emotional element (assensus), which includes “a deep conviction [and affirmation] of the truth”; and a volitional element (fiducia), which involves “a personal trust in Christ as Saviour and Lord, including a surrender . . . to Christ.”  Augustus Strong argues similarly concerning the volitional element of faith, saying that it involves “surrender of the soul, as guilty and defiled, to Christ’s governance.”  Modern popular theology tends to recognize the intellectual and emotional elements of faith but dispenses with the volitional aspect. Yet faith is not true faith if it lacks this attitude of surrender to Christ’s authority.
Writing about the verb “to obey” (peithō), W. E. Vine says:
Peithō and pisteuō, “to trust,” are closely related etymologically; the difference in meaning is that the former implies the obedience that is produced by the latter, cp. Hebrews 3:18–19, where the disobedience of the Israelites is said to be the evidence of their unbelief. . . . When a man obeys God he gives the only possible evidence that in his heart he believes God. . . . Peithō in N.T. suggests an actual and outward result of the inward persuasion and consequent faith. 
So the person who has believed will yearn to obey. Because we retain the vestiges of sinful flesh, no one will obey perfectly (cf. 2 Corinthians 7:1; 1 Thessalonians 3:10), but the desire to do the will of God will be ever present in true believers.
Romans 7 is the classic text describing the believer’s struggle with his sinful flesh, and in that passage Paul acknowledged his changed attitude to sin despite the ongoing struggle. He wrote that the desire to do good was his consuming passion as a believer:
I am not practicing what I would like to do, but I am doing the very thing I hate. (Romans 7:15)
The willing [to do good] is present in me. (Romans 7:18)
I joyfully concur with the law of God in the inner man. (Romans 7:22)
I myself with my mind am serving the law of God. (Romans 7:25)
Although the apostle Paul described himself as the “foremost” of sinners (1 Timothy 1:15), those who love reveling in debauchery will not find a kindred spirit with him.