The "line" or cord was spun of threads dyed with cochineal: i. e., of a deep and bright scarlet color. The color would catch the eye at once, and supplied an obvious token by which the house of Rahab might be distinguished. The use of scarlet in the Levitical rites, especially in those more closely connected with the idea of putting away of sin and its consequences (compare e. g., Leviticus 14:4, Leviticus 14:6,Leviticus 14:51; Numbers 19:6), naturally led the fathers, from Clement of Rome onward, to see in this scarlet thread, no less than in the blood of the Passover (Exodus 12:7, Exodus 12:13, etc.), an emblem of salvation by the Blood of Christ; a salvation common alike to Christ's messengers and to those whom they visit.

This line of scarlet thread - תקות חוט השני tikvath chut hashshani. Probably this may mean, this piece of scarlet cloth, or, this cloth (made) of scarlet thread. When the Israelites took the city this piece of red cloth seems to have been hung out of the window by way of flag; and this was the sign on which she and the spies had agreed.

Behold, when we come into the land,.... The land of Canaan, and into this city, into that part of it, as the Septuagint, where her house was, meaning not themselves only, but the people of Israel they belonged to:

thou shall bind this line of scarlet thread in the window which thou didst let us down by; the word by refers either to the scarlet thread they were let down by, said to be a cord, Joshua 2:15; and therefore must be a line twisted with various scarlet threads, as Kimchi; who observes, that according to the Targum, it was the border of a red garment; or to the window through which they were let down, as the Septuagint version; it may refer to both, and the sense be, that the same twisted cord of scarlet thread they were let down by should be bound to the same window they were let down through; only this objection there is to the same window, that it was not towards the city, and so not to be seen when they came into it, but looked over the wall without the city: now as Rahab was an instance of the salvation of sinners by the grace of God, for she was a sinner by birth, by practice, and a notorious one; she was an instance of distinguishing grace, of free and efficacious grace, a singular instance of it; and became a true penitent, a real believer, was a justified person, and saved: so the scarlet thread was an emblem of the blood of Christ, by which salvation is; redemption and all the blessings of grace are through it; justification, remission of sin, reconciliation, and atonement, and safety, and protection from avenging justice, and wrath to come, are only by it: likewise the spies, who are also called "messengers", James 2:25; may represent the ministers of the Gospel, who are the messengers of Christ, and the churches, are sent out by him the antitypical Joshua, men of wisdom, courage, and valour, and are sent as spies to bring to light men and things, who direct to the way of salvation and give the same token of it, Mark 16:16,

and thou shall bring thy father, and thy mother, and thy brethren, and all thy father's household home unto thee; into her house, where the scarlet thread was bound, and where only they would be safe, as the Israelites were in the houses where the blood of the paschal lamb was sprinkled, Exodus 12:23; and so they are safe, and they only, who are under the blood of sprinkling, and partake of the virtue of it.

The first condition was, that when the town was taken Rahab should make her house known to the Israelites, by binding "the cord of this crimson thread," i.e., this cord made of crimson thread, in the window from which she had let them down. The demonstrative "this" leads to the conclusion adopted by Luther and others, that "this cord" is the rope (חבל) mentioned in Joshua 2:15, as no other word had been mentioned to which they could refer; and the fact that nothing has been said about the sign in question being either given or received, precludes the idea that the spies gave the cord to Rahab for a sign. The crimson or scarlet colour of the cord (שׁני equals שׁני תּולעת; see at Exodus 25:4), as the colour of vigorous life, made this cord an expressive sign of the preservation of Rahab's life and the lives of her relations. The second condition was, that when the town was taken, Rahab should collect together her parents, and her brothers and her sisters, into her own house.

Behold, when we come into the land, thou shalt bind this line of scarlet thread in the window which thou didst let us down by: and thou shalt bring thy father, and thy mother, and thy brethren, and all thy father's household, home unto thee.

2:18 Into the land - That is, over Jordan, and near the city. This line of scarlet - Probably the same with which she was about to let them down. Window - That it may be easily discerned by our soldiers.

bring: Heb. gather

2:8-21 Rahab had heard of the miracles the Lord wrought for Israel. She believed that his promises would certainly be fulfilled, and his threatenings take effect; and that there was no way of escape but by submitting to him, and joining with his people. The conduct of Rahab proved that she had the real principle of Divine faith. Observe the promises the spies made to her. The goodness of God is often expressed by his kindness and truth, Ps 117:2; in both these we must be followers of him. Those who will be conscientious in keeping promises, are cautious in making them. The spies make needful conditions. The scarlet cord, like the blood upon the doorpost at the passover, recalls to remembrance the sinner's security under the atoning blood of Christ; and that we are to flee thereto for refuge from the wrath of a justly offended God. The same cord Rahab used for the saving of these Israelites, was to be used for her own safety. What we serve and honour God with, we may expect he will bless, and make useful to us.