Joshua 5:2

2. At that time That is, during the interval of four days between the passage of Jordan and the passover, (see Joshua 4:19, note,) and while their foes are dismayed and panic-stricken. This was a very opportune occasion to perform the rite of circumcision, which for a season unfitted its subjects for military duty.

Circumcise again… the second time This does not imply that there had been a previous time of general circumcising, as some say, at Sinai, but a previous state of circumcision. See Joshua 5:5. The rite was not performed twice on the same individual, but the sense is, Resume again the rite of circumcision as it was practiced forty years ago.

The children of Israel All the males who were born after the Hebrews left Egypt.

Sharp knives Hebrew, knives of rocks, stones, or flints.

Such an instrument was used by Zipporah in circumcising the son of Moses. Exodus 4:25. Knives among rude barbarians are first made of flint. It is probable that this was used in the first circumcision by the patriarchs, and the same instrument was used by Joshua not from necessity for he had iron tools but from deference to ancient custom. It is said also that the wound made with a sharp stone is less liable to inflammation than one made with metal. These knives were to be made for the occasion, as it would not be proper to use in a religious rite instruments employed in common uses. Knives that had been used for other purposes might inoculate the circumcised person with the virus of some disease. Hiob Ludolph, in his history of the Ethiopians, speaks of a tribe of the Alnaei who performed the rite with stone knives as recently as one hundred and sixty years ago. According to the Septuagint version of Joshua 24:30, the stone knives used on this occasion were deposited in the tomb of Joshua as sacred relics. Perhaps some modern geologists would consider them relics of a “stone age.”