This time, however, the point is illustrated by looking at multiple translations of Hermas, Mandates 12.6.2. These are chronological, in order of original publication. Note the emphasized text. I think Ehrman is the most readable. Recall that Holmes is ostensibly an update and revision of Lightfoot/Harmer.

Lightfoot/Harmer: Believe, therefore, on God, ye who by reason of your sins have despaired of your life, and are adding to your sins, and weighing down your life; for if ye turn unto the Lord with your whole heart, and work righteousness the remaining days of your life, and serve Him rightly according to His will, He will give healing to your former sins, and ye shall have power to master the works of the devil. But of the threatening of the devil fear not at all; for he is unstrung, like the sinews of a dead man.
Lightfoot, J. B., & Harmer, J. R. (1891). The Apostolic Fathers. Includes index. (439). London: Macmillan and Co.

Lake: Believe, therefore, in God, though you have renounced your life through your sins, and have added to your sins, and have made your life heavy, that if you ‘turn to the Lord with all your heart, and do righteousness’ for the rest of the days of your life, and serve him in uprightness, according to his will, he will heal your former sins, and you shall have power to master the works of the devil. But do not fear the threat of the devil at all, for he is powerless as the sinews of a dead man.
Lake, K. (1912-13). The Apostolic fathers. The Loeb classical library (2:137). London; New York: Heinemann; Macmillan.

Holmes: So believe in God, you who because of your sins have despaired of your life, and are adding to your sins, and are making your life hard, because if you turn to the Lord with all your heart, and practice righteousness the rest of the days of your life, and serve him rightly according to his will, he will heal your previous sins, and you will have power to conquer the devil’s works. But do not fear the devil’s threats at all, for he is as powerless as a dead man’s sinews.
Holmes, M. W. (1999). The Apostolic Fathers : Greek texts and English translations (Updated ed.) (417). Grand Rapids, Mich.: Baker Books.

Ehrman: You have despaired of your life because of your sins, and increased your sins, and overburdened your life—you should trust in God. For if you turn to the Lord with your whole heart and do righteousness the rest of your days, serving him properly according to his will, he will heal your former sins. And you will be empowered to rule over the works of the devil. But do not fear the devil's threat at all, for he is as weak as a tendon on a corpse.
Ehrman, Bart D. (2003). The Apostolic Fathers. Loeb Classical Library (2:303). Cambridge, MA: Harvard University Press.

The picture that Ehrman provides — "he is as weak as a tendon on a corpse" — is much better than the others that revert to the KJV-ish "sinew" to make the image. The use of "corpse" instead of "dead man" also contributes positively to the picture.

This excerpt from Hermas also reminds me of a bit of a pet peeve of mine. Have you ever been in a Bible study where folks end up dwelling on "Satan" as if he is an omnipotent and omnipresent deity wreaking havoc in all areas of everyone's life simultaneously? It's easy to think so; but I much rather think that many of the things in life that folks like to ascribe to "Satan" are really the result of our struggle against sin. I really don't think the prince of darkness has much personal interest in me; he can surely focus his non-omniscience and non-omnipresence elsewhere to much greater effect. Instead of focusing on attribution of things to "Satan" (whom I am much more comfy just calling "the enemy"), we should instead focus our efforts on believing and serving the one true God.

That's why I like this last portion of Hermas Mandates so much. I think it properly refocuses me on what is important: living in obedience to God, not cowering in fear to the one he has vanquished. I'm not saying that Hermas is canonical (despite its presence in Codex Sinaiticus) and I'm not saying that we should let it unduly influence our doctrines of Satan and demonology. I am saying, though, that the underlying notion and perspective found here is generally healthy and helpful.

The enemy has no power, he is as weak as a tendon on a corpse.

Consider how the Mandates end. Here is Hermas, Mandates 12.6.3-5 (Holmes' translation):

(3) Listen to me, therefore, and fear him who is able to do everything, to save and to destroy, and keep these commandments, and you will live to God.” (4) I said to him, “Sir, now I am strengthened in all the Lord’s commandments, because you are with me. I know that you will crush all the power of the devil, and we will rule over him and prevail over all his works. And I hope, sir, that I am now able to keep these commandments which you have commanded, as the Lord enables me.” (5) “You will keep them,” he said, “if your heart is pure toward the Lord; indeed, all who cleanse their hearts of the vain desires of this world will keep them, and will live to God.”
Holmes, M. W. (1999). The Apostolic Fathers : Greek texts and English translations (Updated ed.) (417). Grand Rapids, Mich.: Baker Books.