“Tie this cord of scarlet thread.” The Hebrew is abrupt; the directions were short and clear. There was no room for error in this communication, it meant life or death. The cord was made of scarlet thread, and is called a “scarlet cord” in Joshua 2:21). It is interesting and unexplained as to how Rahab happened to have a scarlet-colored cord in her house. However, we know from the flax she was drying that she may have made clothes, and scarlet was a common color worn by women, so it does make sense that she could have had scarlet cord in her house.
The Hebrew word translated “cord” is tiqvah (#08615 תִּקְוָה), which has two meanings, and both are appropriate here. The two meanings are “cord, line” and “hope.” In Rahab’s case, she was to tie a “cord” of scarlet thread, which was also her “hope” of being delivered from death, into the window so the Israelite warriors could see it.