This is from the so called Crusader Bible:
Image icon MS M.638, fol. 11v
An Execution, Joshua's Final Commands, Joshua's Passing
Old Testament Miniatures with Latin, Persian, and Judeo-Persian inscriptions
390 x 300 mm
Purchased by J.P. Morgan (1867–1943) in 1916
MS M.638, fol. 11v
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Apparently the illustration is from the Morgan Bible, depicting the execution by Joshua of the Amorite kings. For biblical context, see Joshua 10-11.
According to Wikipedia, "The prevailing scholarly view is that the book of Joshua is not a factual account of historical events."