There have been a number of television shows, movies and various articles on the subject of angels and the demonic in recent years. Most of this material is pure fiction, yet the part that is not fiction is an acknowledgment that they both exist.
As part of the church's catechesis on creation it is necessary to speak of both the angels and the devil, Satan, or the demonic. "The Apostles' Creed professes that God is the 'Creator of heaven and earth.' The Nicene Creed makes it explicit that this profession includes 'all that is, seen and unseen" (Catechism #325).
"The profession of faith of the Fourth Lateran Council (1215) affirms that God from the beginning of time made at once (simul) out of nothing both orders of creatures, the spiritual and the corporeal, that is, the angelic and the earthly, and then (deinde) the human creature, who as it were shares in both orders, being composed of spirit and body" (#327).
The Catechism clearly asserts that "the existence of the spiritual, non-corporeal beings that Sacred Scripture usually calls 'angels' is a truth of the faith" (#328), the witness of Scripture being as unanimous as tradition. In other words, there is no question about it: the angels are real, not the figment of someone's medieval imagination. It is a truth of the faith. This quite simply means that for a Catholic, one must accept this as part of God's revelation. One may not understand it, but one must accept it on faith, and then seek the understanding that faith can ultimately bring. Although, it being understood, that we'll never understand in this life God and all his mighty works perfectly. We would have to be God to understand him perfectly.
The angels are creatures, pure spiritual beings whose mission or office is to be messengers and servants of God (#329). "As purely spiritual creatures angels have intelligence and will: they are personal and immortal creatures, surpassing in perfection all visible creatures, [with the exception of the Mother of God] as the splendor of their glory bears witness" (#330).
The Lord Jesus Christ is the author, center, and end of all creation including the angelic world. They are "his angels." As the Catechism teaches, "they belong to him because they were created through and for him...They belong to him still more because he has made them messengers of his saving plan" (#331).
The existence and activity of the angels is more than obvious in both the Old and New Testaments. To say, by the way, that they are mere "literary figures" in Scripture in the name of so-called biblical scholarship is an affront to and an attack upon true scholarship. All Scripture has to be read as a totality, in the light of tradition, and applying the analogy of faith. When this is done it is clear that the church's teaching is constant in that angels are real beings, not mere literary devices. They have played a key role in salvation history:
"Angels have been present since creation...They closed the earthly paradise; protected Lot; saved Hagar and her child; stayed Abraham's hand; communicated the law...led the People of God; announced birth's and callings; assisted the prophets...; the Angel Gabriel announced the birth of the Precursor and that of Jesus himself (#332).
"From the Incarnation to the Ascension, the life of the Word incarnate is surrounded by the adoration and service of angels...[They announced his birth to the poor shepherds];...they protect Jesus in his infancy, serve him in the desert, strengthen him in his agony in the garden...It is the angels who evangelize' by proclaiming the Good News of Christ's Incarnation and Resurrection. They will be present at Christ's return, which they will announce, to serve at his judgment (# 333).
These events wherein the angels exercised their ministry as messengers and servants of the Lord are real, as the church asserts. The entire life of the church, the mystical body of Christ, is likewise aided and benefited by the mysterious and powerful help of the angels (#334).
In addition, each and every person benefits from the ministry of the angels. The church has long taught that we have a "guardian angel" to guide and protect us through life. "From infancy to death human life is surrounded by their (the angels') watchful care and intercession. Beside each believer stands an angel as protector and shepherd leading him to life." Already here on earth the Christian life shares by faith in the blessed company of angels and men united in God.
The existence and malevolent activity of the devil or Satan and the fallen angels or demons is likewise a teaching of the church that must be accepted by all. "The Church teaches that Satan was at first a good angel, made by God: The devil and the other demons were indeed created naturally good by God, but they became evil by their own doing (#391).
Through the misuse of the gifts of intellect and free will the devil (Lucifer) and those who went his way chose irrevocably to reject God and his reign. Their choice is irrevocable because of their higher nature. Men get a second chance, and many more than that, but the angels clearly saw what they were doing. Hence, "There is no repentance for the angels after their fall, just as there is no repentance for men after death" (#393).
Christ came to cast out the evil one and his works of lying and death, and did so through the humble obedience which led him always to accept the Father's will, even unto the death of the cross. The essence of the diabolic is that pride and arrogance which leads to disobedience. This leads to fracturing and division. Stepping outside of the truth who is God himself results in this division.
Those who are most powerful in Christ through his church, which is called to fight against "the liar and father of lies, the murderer from the beginning" (cf.. Jn 8:42f) (the devil), are those who are most humbly obedient to God's authority working through the church. The devil can do nothing when he comes up against those who obey most humbly Christ's church and her teachings. On the other hand, he is most powerful and untiringly active working through those who imagine themselves to be above the church's teaching authority. Humility leads to obedience, which leads to life. Pride leads to disobedience, which leads to death. This is the lesson of the book of Genesis. It is the lesson of the cross.
With the angels of the Lord we humbly and obediently praise and give thanks to the Father through Christ in the power of the Holy Spirit for all that God's creative and redemptive power has wrought.