“Those who fall cannot give the excuse that the trials or temptations they encounter are greater then the power they have to defeat them.” 

The tests that the devil brings upon us do not surpass the human power to endure. For if it surpasses this power, man would be at no fault for not enduring and overcoming them.

So those who fall cannot give the excuse that the trials or temptations encountered, were greater then the power they had to defeat them.

Of course, things get complicated, given that man cannot overcome these trials by his power alone, but also with the power of God.

And the power given to man form Above, is granted as such, not to make his effort useless or to require an effort that man could not bare.

Exceptions exist with the wonders (miracles) that are worked though some. But even in these cases, the supernatural power grated to man, is at the measure of his supernatural faith.

However, the line between the order of nature and the supernatural is difficult to draw and (is) very subtle.

In the faithful, this supernatural power, penetrating their being, lifts up their powers at various levels. “

(Father Dumitru Stăniloae, 329 note to “The Ascetic Words” of Saint Isaac the Syrian , Philokalia IX)