Now Jericho was straitly shut up, etc Jericho is said to be shut up, because the gates were not opened: as in time of war cities are guarded with more than usual care. It is added, by way of emphasis, that they were sealed, or locked up, [1] as if it were said that the inhabitants were attentive in watching, so as not to be taken by surprise. Hence, as it could not be taken by stratagem, the only hope of taking it was by open force. This tends to display the goodness of God to the children of Israel, who would have been worn out by a long and difficult siege, had not a substitute been early provided from heaven. Meanwhile there was a danger, lest being forced into a corner, they might be consumed by want and famine, as there was no means of obtaining food and provender in a hostile region. The Lord, therefore, that they might not sit down despondently before one city, assisted them by an extraordinary miracle, and opened up an entrance to them by throwing down the walls, that they might thereafter have the greater confidence in attacking other cities. We now see the connection between the two first verses, in the one of which it is said, that Jericho was shut up, and the children of Israel thus prevented from approaching it, while in the other God promises that he will take it for them. He makes this promise with the view of preventing them from tormenting themselves with anxious thoughts. In one word, God, by this easy victory at the outset, provides against their giving way to despondency in future. We, at the same time, perceive the stupidity of the inhabitants, who place their walls and gates as obstacles to the divine omnipotence; as if it were more difficult to break up or dissolve a few bars and beams than to dry up the Jordan.

Footnotes

1 - The Septuagint has sunkekleismene kai ochuromene, "completely closed and made sure, by being barred or barricaded." -- Ed.

This verse is strictly parenthetical. It is inserted to explain the declaration commenced Joshua 5:14, and interrupted by Joshua's question and obeisance Joshua 5:14-15, but resumed in Joshua 6:2.
Straitly shut up - See the margin, i. e., not only shut, but barred and bolted.

Now Jericho was straitly shut up - The king of Jericho, finding that the spies had escaped, though the city was always kept shut by night, took the most proper precaution to prevent every thing of the kind in future, by keeping the city shut both day and night, having, no doubt, laid in a sufficiency of provisions to stand a siege, being determined to defend himself to the uttermost.

Now Jericho was straitly (a) (b) shut up (c) because of the children of Israel: none went out, and none came in.
(a) That none could go out.
(b) That none could go in.
(c) for fear of the Israelites.

Now Jericho was straitly shut up, because of the children of Israel,.... Or "it shut up", or "was shutting, and was shut up" (u); that is, the king and the inhabitants shut it up within; the Targum says with iron doors, and bars of brass, and it was blocked up without by the children of Israel:
none went out and none came in; none of their forces went out to make a sally on the Israelites, or to seek to make peace with them; nor any of their neighbours went in to them, to carry them any provision, or to assist them, or to be sheltered by them, not being able to do it because of the camp of Israel.
(u) "claudens et clausa", Montanus, Vatablus.

Jericho resolves Israel shall not be its master. It shut itself up, being strongly fortified both by art and nature. Thus were they foolish, and their hearts hardened to their destruction; the miserable case of all that strengthen themselves against the Almighty. God resolves Israel shall be its master, and that quickly. No warlike preparations were to be made. By the uncommon method of besieging the city, the Lord honoured the ark, as the symbol of his presence, and showed that all the victories were from him. The faith and patience of the people were proved and increased.

JERICHO SHUT UP. (Joshua 6:1-7)
Now Jericho was straitly shut up--This verse is a parenthesis introduced to prepare the way for the directions given by the Captain of the Lord's host.

When Joshua had taken off his shoes, the prince of the army of God made known to him the object of his coming (Joshua 6:2-5). But before relating the message, the historian first of all inserts a remark concerning the town of Jericho, in the form of an explanatory clause, for the purpose of showing the precise meaning of the declaration which follows.
(Note: If there is any place in which the division of chapters is unsuitable, it is so here; for the appearance of the prince of the angels does not terminate with Joshua 5:15, but what he had come to communicate follows in Joshua 6:2-5, and Joshua 6:1 merely contains an explanatory clause inserted before his message, which serves to throw light upon the situation (vid., Ewald, 341). If we regard the account of the appearance of the angel as terminating with Joshua 5:15, as Knobel and other commentators have done, we must of necessity assume either that the account has come down to us in a mutilated form, or that the appearance ceased without any commission being given. The one is as incredible as the other. The latter especially is without analogy; for the appearance in Acts 10:9., which O. v. Gerlach cites as similar, contains a very distinct explanation in Acts 10:13-16.)
This meaning is to be found not merely in the fact that the Lord was about to give Jericho into the hands of the Israelites, but chiefly in the fact that the town which He was about to give into their hands was so strongly fortified.

"Jericho was shutting its gates (vid., Judges 9:51), and closely shut." The participles express the permanence of the situation, and the combination of the active and passive in the emphatic form מסגּרת (lxx συγκεκλεισμένη καὶ ὠχυρωμένη; Vulg. clausa erat atque munita) serves to strengthen the idea, to which still further emphasis is given by the clause, "no one was going out and in," i.e., so firmly shut that no one could get out or in.