7 But the reply is made: Why did He say, "Turn not aside to the right hand, nor to the left," when he clearly ought rather to have said, Keep to the right hand, and turn not off to the left, if the right-hand paths are good? Why, do we think, except this, that the paths on the right hand are so good that it is not good to turn off from them, even to the right? For that man, indeed, is to be understood as declining to the right who chooses to attribute to himself, and not to God, even those good works which appertain to right-hand ways.
Hence it was that after saying, "For the Lord knows the ways on the right hand, but those on the left hand are perverse," as if the objection were raised to Him, Wherefore, then, do you not wish us to turn aside to the right? He immediately added as follows: "He will Himself make your paths straight, and will direct your ways in peace." Understand, therefore, the precept, "Make straight paths for your feet, and order your ways aright," in such a sense as to know that whenever you do all this, it is the Lord God who enables you to do it. Then you will not turn off to the right, although you are walking in right-hand paths, not trusting in your own strength; and He will Himself be your strength, who will make straight paths for your feet, and will direct your ways in peace.
Source: Letters (New Advent)