"If a man also strive for masteries, yet is he not crowned, except he strive lawfully."
2 Timothy 2:5
In other words, it is not a bare striving, but a striving according to certain rules. But these rules are spiritual rules; and being spiritual rules, exclude everything of sense, reason, and nature. Now man, in an unregenerate condition, whether he be in a state of profanity, or in a state of profession, has no spiritual knowledge of the way by which to overcome. He may strive against his lusts; he may endeavor to overcome those things that conscience bears testimony against; but he is not crowned, because he strives not lawfully. He strives in his own strength; contends in his own wisdom; and trusts in his own righteousness. Such strugglers and such overcomers (if overcomers they ever are) are not crowned, because they strive not according to the rules laid down in God's word. This at once excludes all creature righteousness, human wisdom, and natural strength. This takes the crown completely off the creature, and puts it on the head of the Redeemer.
There are certain rules then laid down in the Scripture, according to which we are to fight and to overcome. For instance, the Lord of life and glory is held out in the word as our pattern--"He has left us an example that we should follow his steps." He fought the battle before us; and he gained the victory, not for himself only, but for his people; and he has left us here below to walk in his footsteps, and to overcome in the same way as he did; as we read, "To him that overcomes will I grant to sit with me in my throne; even as I also overcame, and am set down with my Father in his throne." All striving then, and all overcoming, which is not in the steps of Christ, and precisely (in a measure) in the same way in which Jesus strove and overcame, is not the overcoming which is crowned with God's approbation.