1849 EXOUSIA (102): the authority or the right to act. Inasmuch as God has both the authority and the power to do as he pleases no serious harm is done by translating exousia with the word "power" (though incorrect) when reference is to God. But to translate it "power" in reference to humans is an error in translation. (The Greek word for "power" or "ability" is dunamis.) This can be seen when exousia and dunamis occur together in the same passage, being correctly translated "authority" and "power" respectively, as in Lk.4.36, 9.1, 10.19, 1Co.15.24, Eph.1.21, 1Pe.3.22, Rev.12.10, 13.2 and 17.13.
Yesu claimed, "All authority (exousia) in heaven and on earth was given to me." (Mt.28.18). But exousia refers to the authority of Satan or darkness in Lk.22.53, Act.26.18, Eph.2.2 & Col.1.13. If Yesu has all authority, how can Satan have any? Eph.1.21, states that Yesu is "Far ABOVE all authority and power and masters and every name being named...", thus showing that other authorities exist, including Satan and humans, but that they are UNDER Yesu. So then, in Jn.1.12 exousia can (and for accuracy, should) be translated by the word "authority" rather than "power" to show that Yesu has not just given humans the ability to receive him but has given humans the right to do so!
In God's First Century Revelation (FCR) authority is conveyed (given) by one who has the authority to (exousia) to delegate it. Thus, in Mt.28.18 the one giving authority to Yesu is understood to be God the Father, with whom "authority" originates (cf., Mt.9.8 and 1Co.15.27-28).
Note that in the FCR exousia (authority) describes something given to a person, it is not the person himself. For example, Mt.28.18 does not state that Yesu IS the authority, but that he WAS GIVEN all authority. No human is described to be an "authority" in the FCR, unless by metonymy. Thus in Rom.13.1 the ones who received authority were given it by someone else (God in this passage). So then, exousia in Rom.13.1 would more appropriately be translated something like, "those having authority." Civil leaders are appointed by God (Dan.4.17,25,32,35 and Jn.19.10-11), and are limited to the exousia given to them by God. So, FCR "authority" (whether civil, religious or otherwise) which is not "authorized" by God is usurped authority, as in Eph.6.12.
THE RIGHT, OR AUTHORITY TO ACT:
A PERSON TO WHOM AUTHORITY HAS BEEN DELEGATED:
1850 EXOUSIAZO (4): to have authority or be under authority. Comp. "exercise authority" (2715 katexousiazo).