"Wherefore we ought always to 'guard' ourselves, lest at any time we should fall asleep. For 'Lo' (it is said) 'he that keepeth Israel shall neither slumber nor sleep' and 'Do not suffer thy foot to be moved.' He did not say, 'be not moved' but 'do not thou suffer.' The suffering depends then on ourselves, and not on any other. For if we will stand 'steadfast and unmoveable' we shall not be shaken. What then? Does nothing depend on God? All indeed depends on God, but not so that our free-will is hindered. 'If then it depend on God,' (one says), 'why does He blame us?' On this account I said, 'so that our free-will is not hindered.' But when we have chosen, then great is the assistance he brings to us....
And secondly the other explanation may be given, that he speaks of all as His, whose the greater part is. For it is ours to choose and to wish; but God's to complete and to bring to an end. Since therefore the greater part is of Him, he says all is of Him, speaking according to the custom of men. For so we ourselves do. I mean for instance: we see a house well built, and we say the whole is the Architect's doing, and yet certainly it is not all his, but the workmen's also, and the owners', who supplies the materials, and many others', but nevertheless since he contributed the greatest share, we call the whole his. So then it is in this case also. Again, with respect to a number of people, where the many are, we say ALL are: where few, nobody. So also Paul says, 'not of him that willeth, nor of him that runneth, but of God that showeth mercy.'
And herein he establishes two great truths: one, that we should not be lifted up by what we do well: the other that when we do well, we should attribute to God the cause of our well-doing. Therefore even thou run (he would say), even shouldst thou be very earnest, do not consider that the well doing is thine own. For if thou obtain not the impusle that is from above, all is to no purpose. Nevertheless that thou wilt attain that which thou earnestly strivest after is evident; so long as thou runnest, so long as thou willest.
He did not then assert this, that we run in vain, but that, if we think the whole to be our own, if we do not assign the greater part part to God, we run in vain. For neither hath God willed that the whole should be His, lest He should appear to be crowning us without cause: nor again our's, lest we should fall away to pride. For if when we have the smaller share, we think much of ourselves, what should we do if the whole depended on us?"
-St. John Chrysostom