וַיֹּ֣אמֶר ׀ לֹ֗א כִּ֛י אֲנִ֥י שַׂר־צְבָֽא־יְהוָ֖ה עַתָּ֣ה בָ֑אתִי וַיִּפֹּל֩ יְהוֹשֻׁ֨עַ אֶל־פָּנָ֥יו אַ֙רְצָה֙ וַיִּשְׁתָּ֔חוּ וַיֹּ֣אמֶר ל֔וֹ מָ֥ה אֲדֹנִ֖י מְדַבֵּ֥ר אֶל־עַבְדּֽוֹ׃
Ed egli rispose: «No, io sono il capo dell'esercito del Signore; ora sono venuto». E Giosuè cadde con la faccia a terra, si prostrò e gli disse: «Che cosa dice il mio signore al suo servo?»
Mishneh Torah, Prayer and the Priestly Blessing
When performing the rite of "falling on the face", after the service, some fall on the face, some prostrate themselves. The latter is forbidden on a stone floor, except in the Temple of Jerusalem, as has been explained in the laws concerning Idolatry. [Even] a worthy person may not fall on his face unless he is conscious that he is a righteous man like Joshua.*(Joshua 5:14) “And Joshua fell on his face to the earth, and did worship.” He should only incline his face somewhat, but not press it against the floor. It is permissible to recite the service of prayer in one spot and "fall upon the face" elsewhere.