Biete Debre Sina — the House of Mount Sinai, also known as Biete Mikael — is one of the eleven rock-hewn churches of the northern group at Lalibela and one of the largest in that cluster. It is carved from the same red volcanic tufa as its neighbours and shares a courtyard with Biete Maryam, to which it is connected by a short passage. The church is dedicated jointly to Mount Sinai and the archangel Michael, and it holds particular significance during the feast of Saint Michael, which occurs monthly in the Ethiopian calendar.
The interior is spacious by Lalibela standards, with carved columns dividing the nave from the aisles and traces of painted decoration on the walls. The ceiling retains geometric patterns that are among the better-preserved examples of early Ethiopian church painting. Biete Debre Sina is in continuous liturgical use, and the priests who serve it are usually present during daylight hours. The church is included in the standard guided tour of the northern complex and is best seen as part of a morning visit when the light in the courtyard is strongest.