What is "by virtue of"

Virtue \Vir"tue\ (?; 135), n. [OE. vertu, F. vertu, L. virtus strength, courage, excellence, virtue, fr. vir a man. See Virile, and cf. Virtu.]

1. Manly strength or courage; bravery; daring; spirit; valor. [Obs.]
   --Shak.

   Built too strong For force or virtue ever to expugn.
   --Chapman.

2. Active quality or power; capacity or power adequate to the production of a given effect; energy; strength; potency; efficacy; as, the virtue of a medicine.

   Jesus, immediately knowing in himself that virtue had gone out of him, turned him about.
   --Mark v. 30.

   A man was driven to depend for his security against misunderstanding, upon the pure virtue of his syntax.
   --De Quincey.

   The virtue of his midnight agony.
   --Keble.

3. Energy or influence operating without contact of the material or sensible substance.

   She moves the body which she doth possess, Yet no part toucheth, but by virtue's touch.
   --Sir. J. Davies.

4. Excellence; value; merit; meritoriousness; worth.

   I made virtue of necessity.
   --Chaucer.

   In the Greek poets, . . . the economy of poems is better observed than in Terence, who thought the sole grace and virtue of their fable the sticking in of sentences.
   --B. Jonson.

5. Specifically, moral excellence; integrity of character; purity of soul; performance of duty.

   Virtue only makes our bliss below.
   --Pope.

   If there's Power above us, And that there is all nature cries aloud Through all her works, he must delight in virtue.
   --Addison.

6. A particular moral excellence; as, the virtue of temperance, of charity, etc. ``The very virtue of compassion.''
   --Shak. ``Remember all his virtues.''
   --Addison.

7. Specifically: Chastity; purity; especially, the chastity of women; virginity.

   H. I believe the girl has virtue. M. And if she has, I should be the last man in the world to attempt to corrupt it.
   --Goldsmith.

8. pl. One of the orders of the celestial hierarchy.

   Thrones, dominations, princedoms, virtues, powers.
   --Milton.

   Cardinal virtues. See under Cardinal, a.

   In virtue of, or By virtue of, through the force of; by authority of. ``He used to travel through Greece by virtue of this fable, which procured him reception in all the towns.''
   --Addison. ``This they shall attain, partly in virtue of the promise made by God, and partly in virtue of piety.''
   --Atterbury.

   Theological virtues, the three virtues, faith, hope, and charity. See
   --1 Cor. xiii. 13.

prep. (context idiomatic English) because of; on the grounds of; by reason of; due to; based on