At that time - on the encampment being made after the passage.
The Lord said unto Joshua, Make thee sharp knives , [ charbowt tsuriym , sharp knives (cf. Psalms 89:44, "edge of the sword"); but the Septuagint has machairas petrinas ek petras akrotomou, stone knives, of sharp-pointed stone; taking tsuwr in the sense of a rock, sharp and precipitous. So also Vulgate, Syriac, and Arabic render the word] - stone knives; i:e., prepare, make them ready. Flints have been used an the early times of all people; and although the use of iron was known to the Hebrews in the days of Joshua, probably the want of a sufficient number of metallic implements dictated the employment of flints on this occasion (cf. Exodus 4:25). Harmer ('Observations,' 4:, p. 167) suggests another, though a fanciful, reason. Those who have given an account of the Egyptian way of embalming, tell us that it was an Ethiopian stone, called basaltes, that was used for opening the body to be embalmed, by which embalming it acquired a sort of immortality. In this view, might not Joshua be enjoined to use a like kind of knives for the circumcising of the Israelites, which circumcision the Jews of later times, at least, looked upon as a token and pledge of their resurrection from the dead, never to return to corruption? The precept to use stone knives might be intended to give some expectation of this nature.' Stone knives are still in Ethiopia (Abyssinia) used for religious purposes.
Circumcise again the children of Israel the second time. - literally, return and circumcise. The command did not require him to repeat the operation on those who had undergone it, but to resume the observance of the rite, which had been long discontinued. The language, however, evidently points to a general circumcising on some previous occasion, which, though unrecorded, must have been made before the celebration of the Passover at Sinai (cf. Exodus 12:48; Numbers 9:5), as a mixed multitude accompanied the camp. "The second time" of general circumcising was at the entrance into Canaan.