The "Apparition of the Virgin to St. Bernard" or the "Vision of St. Bernard" is a wonderful Renaissance painting by Filippino Lippi (c. 1485). I keep thinking about writing a list of great paintings you can see for free in Florence, and this one would be near if not at the top (Pontormo's Deposition in Santa Felicità is another favorite). It is just inside the door, on the left, of the Badia (Abbey) Fiorentina, one of the oldest churches in Florence. The Badia is "closed" to visitors except for Monday afternoons, after 3:00 PM - but it is well worth a visit, for the Lippi, the several works by Mino da Fiesole, and the rest of the art and architecture (you can probably enter the church on other days and hours, as long as there is not a service taking place - it is open for worship all day long).
This painting depicts a visit from the Virgin to St. Bernard as he writes about the annunciation - it is an annunciation in itself, but with Mary visiting the Saint to "announce" his salvation. It is full of symbolism and detail and really needs to be seen in person to be fully appreciated. It is a marvel (and a delight) that a painting of this significance and beauty still hangs in this church and has not somehow been placed in a museum.