As to their first estate (status original is) all angels were originally created equally righteous, good, and holy; for they were to glorify God and render Him holy service (status gratiae). That means that in the beginning all angels were positively good, not morally indifferent, nor tainted by a proclivity to evil. This is clear from the divine verdict "very good," Gen. 1, 31. That there are now two classes of angels, the good and the evil, is due to the fact that some angels did not remain in the original state, but of their own accord fell away from God into sin. From the state of grace (status gratiae) they thus passed into the state of misery (status miseriae).
The good angels are those who persevered in the goodness, righteousness, and holiness in which they were first created. They have been confirmed by God in that which is good (in bono confirmati) as a gracious reward for their obedience, so that they can no longer lose their goodness and become evil (non posse peccare). Thus the good angels reached the goal for which they were originally created; for they forever behold God in holy service, having passed from the state of grace into the state of glory (status gloriae). This truth is taught in Matt. 18, 10; 6, 10; 1 Tim. 5, 21; Luke 20, 36; Gal. 1, 8.
Since Scripture identifies the good angels with the "elect angels" (1 Tim. 5, 21), they persevered in their concreated righteousness and holiness in accord with God's eternal election. However, Scripture nowhere teaches that the evil angels fell into sin because from eternity they were predetermined to damnation; on the contrary, the evil angels left their own habitation, Jude 6, or sinned, of their own accord.
By evil angels we, then, mean those angels who did not persevere in their concreated wisdom and righteousness, but of their own free will turned away from God, became perpetual enemies of God and man, and have been divinely doomed to be plagued with eternal torments (in malo confirmati). The eternal punishment of the evil angels is taught in Matt. 25, 41; Rev. 20, 10; 2 Pet. 2, 4; Jude 6. By what special motive the disobedience of the evil angels was prompted Scripture does not teach with certainty; but it is probable (ratio probabilis) that it was their impious pride which moved them to apostatize from God. The time when the evil angels first sinned cannot be determined with certainty; but their rebellion occurred before the fall of man, since man's fall into sin was instigated by the devil, Gen. 3, 1-14; John 8, 44. That the evil angels can never be restored to holiness and happiness is a fact known also to them, Matt. 8, 29 and should not be gainsaid by men (Universalism), since Scripture emphatically describes the fire which has been prepared for the devil and his angels as an everlasting fire, Matt. 25, 41. While the good angels were confirmed in bliss when they entered into the state of glory, Matt. 18, 10; 25, 31, the evil angels, when entering into the state of misery, became hardened in evil, so that they incessantly think perversely of God and divine things. Hollaz: "The evil angels know God, but they dreadfully shudder at the divine knowledge," Jas. 2, 19.
To the question "Why may not the wicked angels be restored to favor?" Gerhard replies: "It is better to proclaim the wonderful philanthropy and mercy of the Son of God towards the fallen race of man ... than to scrutinize beyond due limits the causes of that most just judgment by which God delivered the angels who had fallen away from Him to be cast in chains of darkness into hell, reserved for judgment." Doctr. Theol., p. 215.