The Bible has much to say about Angels. Most books in scripture contain references to angelic visitations or ministry. Angels minister on behalf of believers. We are not to worship them or pray to them. We are not to be afraid of angels. Angels announced the birth of Christ. They ministered to Jesus after His temptation. An angel released the Apostle Peter from prison when the early church was praying.
There is good reason to believe that angels probably do sing, even though scripture does not say yea or nay. Watch the full sermon video.