Benefit from Sin

Berachos (31b) If Thou wilt indeed look. R. Eleazar said: Hannah said before G-d,: Sovereign of the Universe, if Thou wilt look, it is well, and if Thou wilt not look, I will go and shut myself up with someone else in the knowledge of my husband Elkanah, and as I shall have been alone they will make me drink the water of the suspected wife, and Thou canst not falsify Thy law, which says, She shall be cleared and shall conceive seed. Now this would be effective on the view of him who says that if the woman was barren she is visited. But on the view of him who says that if she bore with pain she bears with ease, if she bore females she now bears males, if she bore swarthy children she now bears fair ones, if she bore short ones she now bears tall ones, what can be said? As it has been taught: She shall be cleared ad shall conceive seed: this teaches that if she was barren she is visited. So R. Ishmael. Said K. Akiba to him, If that is so, all barren women will go and shut themselves in with someone and she who has not misconducted herself will be visited! No, it teaches that if she formerly bore with pain she now bears with ease, if she bore short children she now bears tall ones, if she bore swarthy ones she now bears fair ones, if she was destined to bear one she will now bear two. What then is the force of If Thou wilt indeed look?  The Torah used an ordinary form of expression.