Make yourself familiar with the angels and behold them frequently in spirit;
for without being seen, they are present with you.
   

St. Francis De Sales

From the Holy Bible

But the old prophet answered, "I am a prophet, too, just as you are. And an angel gave me this message from the Lord: 'Bring him home with you, and give him food to eat and water to drink.' " But the old man was lying to him. 

1 Kings 13:18