The word "powers" comes from the Greek ἐξουσία (exousia), which occurs 103 times in the KJV. Of those, it is translated as "powers" 69 times, and "authorities" 29 times. Examples are found in Jesus (Mt. 7:29), Caesar and the Centurion (Mt. 8:9), the Father (Acts 1:7), and Saul of Tarsus (Acts 26:12). We also see from Hebrews 2:14 that Satan has the power and authority to take human life. And in Revelation 6:8, the "fourth horseman," death, has that same power.
The phrase "principalities and powers" appears three times in the Word of God. They read as follows:
"To the intent that now unto the principalities and powers in heavenly places might be known by the church the manifold wisdom of God" (Eph. 3:10).
"And having spoiled principalities and powers, he made a shew of them openly, triumphing over them in it" (Col. 2:15).
"Put them in mind to be subject to principalities and powers, to obey magistrates, to be ready to every good work" (Titus 3:1).
In the first example, the phrase refers to angelic beings (1 Pet. 1:12). The second refers to Satan and his demons (Gen. 3:15; Ps. 68:18; Isa. 53:12; Mt. 12:29; Rev. 20:10). And the third refers to human government (Rom. 13:1; Col 1:10). Born again believers serve to educate Angels, to testify against Satan, and to be an example before those in authority over us.
I have to ask, "How successful are you and I (God's salt and light) doing at this?"