Like many teenagers, I went through phases of questioning my religious beliefs. Brought up as Christian, I attended the local Baptist Church with the rest of my extended family, but left when I found myself doubting some of the things that I heard and some of the behaviour that I saw. After leaving the congregation of the Baptist Church, I attended a Crusaders group and occasional meetings organised in a local theatre that were modelled on the large-scale rallies held by Billy Graham and other famous evangelists. These meetings encouraged me in my developing agnosticism, as the atmosphere was oppressively emotional and the message was all about being saved from something dreadful.
Having left Christian religious beliefs, I became opposed to those who wanted to talk to me about such matters. On one occasion, when I was away at University, a member of the Christian Union knocked on my door. I welcomed him into my room and was happy to chat about things in general, but not when he started to proselytise. That was a challenge that I couldn't resist, so I fired back with an attack on everything that he was saying to me. It is something that I now feel rather bad about but, at the time, I was pleased to be told that I was the nearest that my visitor had come to the Devil. His reaction reminded me of the warnings I had heard in the preaching of the evangelists.
Recently, I read Billy Graham's book about angels  and took a special interest as I have written about angels with bird wings [2,3], so familiar to us in paintings and sculptures. There is no evidence in The Holy Bible to support these images and Billy Graham confirms this (see below, upper); yet his book has a bird-winged angel on the cover (see below, lower).
The book is an interesting read as it gives an insight into what angels mean to an evangelical Christian like Billy Graham. Here is a very small selection of quotes:
..angels are created spirit beings who can become visible when necessary. They can appear and disappear. They think, feel, will and display emotions.. ..the Bible teaches about them as oracles of God, who give divine or authoritative decisions and bring messages from God to men. To fulfill this function angels have not infrequently assumed visible human form..
..We must be aware that angels keep in close and vital contact with all that is happening on the earth. Their knowledge of earthly matters exceeds that of men. We must attest to their invisible presence and unceasing labors. Let us believe that they are here among us. They may not laugh or cry with us, but we do know they delight with us over every victory in our evangelistic endeavors.
The Bible seems to indicate that angels do not age, and never says that one was sick.. ..The holy angels will never die.
..in some cases in the Old Testament God Himself appeared in human form as an angel.
The Bible.. ..teaches that angels are sexless.
The number of angels remains constant. For the obedient angels do not die. The fallen angels will suffer the final judgement at the time God finishes dealing with them. While we cannot be certain, some scholars estimate that as many as one third of the angels cast their lot with Satan when he mysteriously rebelled against his Creator.
Nothing in Scripture says that angels must eat to stay alive. But the Bible says that on certain occasions angels in human form did indeed eat.
While it is partly speculative, I believe that angels have the capacity to employ heavenly celestial music.. .. I think before we can understand the music of heaven we will have to go beyond our earthly concept of music. I think most earthly music will seem to us to have been in the "minor key" in comparison to what we are going to hear in heaven.
You must read the whole book to gain more information and also to experience the tone that is used. It is similar to the emotive language of a Billy Graham rally and, as we see from the quotation above, is "partly speculative". One of the most important statements in the book is this:
Satan often works by interjecting a question to raise doubts. It is deadly to doubt God's Word!
I take this to mean that we shouldn't question and that is difficult for me as my training as a scientist has questioning at its heart. In reading Billy Graham's book, I was reminded repeatedly about his constant concern about Satan's influence in the World and of our need to be saved. It took me back to my experience as an undergraduate student.
By the way, I don't believe that angels exist. That does not mean that I disrespect those that do believe in angels; rather I regard it as being a matter of personal choice. Sorry, Billy.
 Billy Graham (1975) Angels: God's Secret Agents. London, Hodder & Stoughton.