'Angels' in Greek mean 'Messengers'. In Bible, heavenly angels are mentioned as messengers of god. Christmas angels are perhaps the most popular form of angels that are used in our celebrations. Angels are believed to be immortal, who live in Heaven, and act as intermediaries between God and Humankind. Traditionally, pictures and poems on angels portray them having human bodies with wings sprouting from their backs. 'Wings' are said to symbolize Innocence, Virtue, Purity, Peace and Love, which place them above Humans though they are still under God. It was the Hebrew Bible or the Old Testament of Christianity, which first mentions that angels had a human body and angel wings and could fly.
According to the New Testament, when people are sorry for their sins, angels rejoice. In Bible, nine ranks of angels are mentioned with Seraphim and Cherubim angels on top. Angels are headed by a chief angel known as an Archangel whose name is Saint Michael. We all have our guardian angels or angel guardians who protect us, look after us and comfort us in times of distress. It was in 1100 to 1200 AD when Christian doctrine about angels evolved rapidly, as in the teachings of Saint Thomas Aquinas. Saint Thomas believed that angels fill the gap between God and mankind; they are countless and immortal. According to Saint Thomas, angels have perfect knowledge except things that can depend on human choice and things that only God knows.