John Calvin Commentary Hebrews 11:31

"By faith Rahab the harlot perished not with them that were disobedient, having received the spies with peace." — Hebrews 11:31 (ASV)

By faith the harlot Rahab, etc. Although at first glance, this example may seem, due to the low status of the person, scarcely deserving notice, and even unworthy of being recorded, yet it was not inappropriately, nor without reason, cited by the Apostle. He has until now shown that the Patriarchs, whom the Jews most honored and venerated, did nothing praiseworthy except through faith; and that all the benefits God conferred on us, even the most remarkable, have been the fruits of the same faith: but he now teaches us that a foreign woman, not only of a humble status among her own people but also a harlot, had been adopted into the body of the Church through faith.

It therefore follows that those who are most exalted are of no account before God unless they have faith; and that, on the other hand, those who are scarcely allowed a place among the profane and the reprobate are by faith introduced into the company of angels.

Moreover, James also bears testimony to the faith of Rahab (James 2:25). It may be easily concluded from sacred history that she was endowed with true faith. For she professed her full conviction of what God had promised to the Israelites; and of those whom fear kept from entering the land, she asked pardon for herself and her friends, as if they were already conquerors. In all this, she did not consider men, but God Himself. The evidence of her faith was that she received the spies at the risk of her life: then, by means of faith, she escaped safely from the ruin of her own city. She is mentioned as a harlot, in order to amplify the grace of God.

Some, indeed, translate זונה as 'hostess,' as if she kept a public house or an inn. But as the word means 'harlot' everywhere in Scripture, there is no reason why we should explain it otherwise in this place. The Rabbis, thinking it strange and disgraceful to their nation if it were said that the spies entered the house of a harlot, invented this forced meaning. But this fear was groundless. For in the history of Joshua, this word, 'harlot,' is expressly added so that we may know that the spies came into the city of Jericho secretly and concealed themselves in a harlot’s house. However, this must be understood as referring to her past life, for faith is evidence of repentance.