A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
jos 5:1THE CANAANITES AFRAID. (Jos 5:1)
the kings of the Amorites, which were on the side of Jordan westward, and all the kings of the Canaanites, which were by the sea--Under the former designation were included the people who inhabited the mountainous region, and under the latter those who were on the seacoast of Palestine.
heard that the Lord had dried up the waters of Jordan . . . that their heart melted--They had probably reckoned on the swollen river interposing for a time a sure barrier of defense. But seeing it had been completely dried up, they were completely paralyzed by so incontestable a proof that God was on the side of the invaders. In fact, the conquest had already begun in the total prostration of spirit among the native chiefs. "Their heart melted," but unhappily not into faith and penitent submission.
jos 5:2CIRCUMCISION IS RENEWED. (Jos 5:2-12)
At that time--on the encampment being made after the passage.
the Lord said unto Joshua, Make thee sharp knives--Stone knives, collect and make them ready. Flints have been used in 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 (compare Exo 4:25).
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 (compare Exo 12:48; Num 9:5), as a mixed multitude accompanied the camp. "The second time" of general circumcising was at the entrance into Canaan.
jos 5:3at the hill--probably one of the argillaceous hills that form the highest terrace of the Jordan, on a rising ground at the palm forest.
jos 5:4this is the cause why Joshua did circumcise--The omission to circumcise the children born in the wilderness might have been owing to the incessant movements of the people; but it is most generally thought that the true cause was a temporary suspension of the covenant with the unbelieving race who, being rejected of the Lord, were doomed to perish in the wilderness, and whose children had to bear the iniquity of their fathers (Num 14:33), though, as the latter were to be brought into the promised land, the covenant would be renewed with them.
jos 5:8when they had done circumcising all the people--As the number of those born in the wilderness and uncircumcised must have been immense, a difficulty is apt to be felt how the rite could have been performed on such a multitude in so short a time. But it has been calculated that the proportion between those already circumcised (under twenty when the doom was pronounced) and those to be circumcised, was one to four, and consequently the whole ceremony could easily have been performed in a day. Circumcision being the sign and seal of the covenant, its performance was virtually an investment in the promised land, and its being delayed till their actual entrance into the country was a wise and gracious act on the part of God, who postponed this trying duty till the hearts of the people, animated by the recent astonishing miracle, were prepared to obey the divine will.
they abode in their places . . . till they were whole--It is calculated that, of those who did not need to be circumcised, more than fifty thousand were left to defend the camp if an attack had been then made upon it.
jos 5:9the Lord said unto Joshua, This day have I rolled away the reproach of Egypt--The taunts industriously cast by that people upon Israel as nationally rejected by God by the cessation of circumcision and the renewal of that rite was a practical announcement of the restoration of the covenant [KEIL].
Gilgal--No trace either of the name or site is now to be found; but it was about two miles from Jericho [JOSEPHUS], and well suited for an encampment by the advantages of shade and water. It was the first place pronounced "holy" in the Holy Land (Jos 5:15).
jos 5:10kept the passover on the fourteenth day of the month at even--The time fixed by the law (see on Exo 12:17; Lev 23:5; Num 28:16). Thus the national existence was commenced by a solemn act of religious dedication.
jos 5:11And they did eat of the old corn of the land--found in storehouses of the inhabitants who had fled into Jericho.
parched corn--new grain (see on Lev 23:10), probably lying in the fields. Roasted--a simple and primitive preparation, much liked in the East. This abundance of food led to the discontinuance of the manna; and the fact of its then ceasing, viewed in connection with its seasonable appearance in the barren wilderness, is a striking proof of its miraculous origin.
jos 5:13AN ANGEL APPEARS TO JOSHUA. (Jos 5:13-15)
when Joshua was by Jericho--in the immediate vicinity of that city, probably engaged in surveying the fortifications, and in meditating the best plan of a siege.
there stood a man over against him with his sword drawn--It is evident from the strain of the context that this was not a mere vision, but an actual appearance; the suddenness of which surprised, but did not daunt, the intrepid leader.
jos 5:14the host of the Lord--either the Israelitish people (Exo 7:4; Exo 12:41; Isa 55:4), or the angels (Psa 148:2), or both included, and the Captain of it was the angel of the covenant, whose visible manifestations were varied according to the occasion. His attitude of equipment betokened his approval of, and interest in, the war of invasion.
Joshua fell on his face . . ., and did worship--The adoption by Joshua of this absolute form of prostration demonstrates the sentiments of profound reverence with which the language and majestic bearing of the stranger inspired him. The real character of this personage was disclosed by His accepting the homage of worship (compare Act 10:25-26; Rev 19:10), and still further in the command, "Loose thy shoe from off thy foot" (Exo 3:5).