New Defender's Study Bible Notes
2:10 we have heard. Even though the two events mentioned by Rahab–the miracle at the Red Sea and the defeat of the Amorite kings–occurred forty years apart, both were known in Jericho. Evidently the people in Canaan, as well as Sihon and his Amorites (Numbers 22:3), had kept informed about the Israelite multitudes during all those years, and were fearful of them.
2:11 God in heaven above. It is remarkable that Rahab, living in a pagan culture all her life, somehow had enough knowledge about the true Creator God to recognize Him as the God of Israel, apparently even exercising saving faith in Him (Hebrews 11:31), a faith which gave her courage to stand alone against her countrymen.
2:18 line of scarlet thread. It is noteworthy that the word translated “line” (here and in Joshua 2:21), which has its first occurrence in the Bible at this point, is never translated “line” anywhere else in the Bible. Its usual meaning is “hope.” For example, “thou art my hope, O Lord GOD” (Psalm 71:5). This thin scarlet line, the scarlet color perhaps speaking of the blood of sacrifice, was thus Rahab’s only hope of deliverance for herself and her loved ones. All others in Jericho perished when the children of Israel took it several days later (Joshua 6:25).