[“Walk before Me, and be faultless”] – Rabbi Levi said: This is analogous to a noblewoman to whom the king said: ‘Pass before me.’ She passed before him, and her face became flushed, [as] she said: ‘Perhaps there is some imperfection to be found in me.’ The king said to her: ‘The only imperfection you have is that the fingernail of your little finger is slightly long. Remove it and the imperfection will be eliminated.’
So, the Holy One blessed be He said to Abraham our patriarch: ‘Your only imperfection is this foreskin. Remove it and the imperfection will be eliminated.’ “I will establish My covenant between Me and you, and will multiply you exceedingly” (Genesis 17:2). “Walk before Me, and be faultless…I will establish My covenant between Me and you…” (Genesis 17:1–2).
Rav Huna in the name of bar Kappara: Abraham sat and expounded a verbal analogy: “Orla is written regarding trees22The prohibition against eating the fruit of a tree the first three years after it has been planted is called orla (Leviticus 19:23). and “orla” is written regarding man;23Abraham was expounding a verbal analogy to ascertain what God meant by orla – in Genesis 17:11, God says: “You shall circumcise the flesh of your orla.” just as orla that is written regarding the tree is in the place that it produces fruit, so orla that is written regarding a person is in the place that he produces offspring.
Rabbi Ḥanina bar Pazi said to him [Rav Huna]: Were verbal analogies, then, transmitted to Abraham? That is a rhetorical question. The explanation is rather that He intimated an allusion to him: “I will establish My covenant between Me and you, and will multiply you exceedingly” – I will establish My covenant between Me and you in the place from which you procreate.