Human reason alone cannot prove the existence of angels with certainty, but, since there are lifeless beings, plants, animals and men on planet Earth, it is rationally convenient and plausible that God also created finite, bodiless, intelligent and free beings. , as a further step between man and God. Today in many non-religious cultural environments it is assumed that there are extra-terrestrial living beings on other planets, if UFOs could exist why couldn't there also be angels?
The existence of intermediate beings who populate with their presence the enormous distance that separates the divine omnipotence from human beings has already been a widespread belief in extra-biblical cultures and in particular in the ancient religions of the peoples close to Israel, but only in monotheistic religions, the so-called "religions of the Book", do these beings take on the characteristics that we attribute to angels. The "spirits" of Egyptian doctrines and Assyrian-Babylonian beliefs have, for the most part, hostile attitudes towards man, who is forced to defend himself through the intervention of a good divinity, and also in the Persian religion, and later in the Greek and Roman ones, which underwent the influence of Hellenism, the relationship between celestial beings and men appears more like a struggle than a positive encounter. In the contrast between these negative and even fearful beings and the "messengers of God" that we encounter in Sacred Scripture, the contribution given by the Bible to the function and presence of angels appears in all its importance.
