Detail of David and Goliath on Southeast Facade
Surb Khach Church
Church of the Holy Cross
Akdamar Island, Van Province, Turkey

A larger image of David and Goliath on Surb Khach Church

Photo by Lostinafrica
Eli (above window), King Saul, Samuel (in roundel), David and Goliath
Saul was at war with the Philistines. Young David, a shepherd, was sent to the war camp with some provisions for his brothers; there he heard Goliath's challenge to a single combat. David volunteered to slay the Philistine with God's help. He went near Goliath, used his sling and hit his forehead, Goliath fell. David used Goliath's sword to kill him. The enemy was dispersed.
The Armenian inscriptions refer to: David the Prophet; and Goliath (AYL ASK - the other, the alien). Between David & Goliath is a crouched deer.
Source: Aghtamar

The "church of the Holy Cross" was built on Aght'amar Island in Lake Van between the years 915 and 921 by the architect-monk Manuel under Armenian King Gagik Artzruni.

Referenced as figure 241 in The military technology of classical Islam by D Nicolle
241A to 241C. Reliefs, A - David and Goliath, B - Mounted Saint, C - Hunters, 915-921 AD, Armenian, in situ Church of the Holy Cross, Aghtamar, Lake Van (Ners Ag).
p174 Lamellar armour may also have been used in Byzantium in the pre-Islamic era39 (Figs. 90, 91 and 556) but its more widespread adoption after the 7th century clearly reflected Muslim military pressure40 (Figs. 212, 220A, 314, 630 and 637). A smaller but equally common kabadion lamellar cuirass was seen in Byzantium from the 10th century41 (Figs. 227, 242, 249, 314, 414 and 608). This could reflect the changing fashions of eastern Islam, where the lamellar kamaband may have been developed in the 10th century, or it could have been the Byzantine original that stimulated the adoption of this latter Iranian form of armour (Figs. 209, 241, 292, 294, 306, 347, 354, 376, 377, 385, 390, 392, 422, 446, 447 and 641).

39. Haldon, "Some Aspects of Byzantine Military Technology from the 6th to the 10th centuries," p. 20.
40. Ibid., pp. 25-26,29 and 46.
41. Ibid., p 36.

Goliath is referenced on p.20, The Armies of Islam 7th-11th Centuries by David Nicolle & Angus McBride
Fine relief at Gagik showing Goliath, heavily armoured with a mail coif or cape over a scale or lamellar cuirass and laminated vambraces. The sword is almost identical to a recently discovered early 11th century example. (Church of Gagik, Lake Van)

See also:
Warrior Saints on the Northwest Facade, Surb Khach Church of the Holy Cross, Akdamar Island, Van Province, Turkish Armenia
Samson Killing a Philistine, Northeast Facade, Surb Khach Church of the Holy Cross, Akdamar Island, Van Province, Turkish Armenia
A Mongolic Horse Archer on the East Wall, 13th century?, Surp Haç Church of the Holy Cross, Aktamar Island, Van Province, Turkey

An Armenian Cavalryman in Armies of the Dark Ages 600-1066 by Ian Heath, based on Goliath on Surb Khach Church