Midras Amsal 21:27: Sifra & Midrash Tehillim

3) [(Vayikra 1:2): "A man, if he offer of you, a sacrifice to the L–rd"] "A man" — to include proselytes; "of you" — to exclude heretics. Why do you see it that way? Why not: "A man" — to include heretics; "of you" — to exclude proselytes? After Scripture includes, it excludes, viz. (Vayikra 1:2): "the children of Israel." Just as the children of Israel are accepters of the covenant, so proselytes — to exclude heretics, who do not accept the covenant. — But why not say: Just as the children of Israel are children of accepters of the covenant, so, heretics — to exclude proselytes, who are not! It is, therefore, written "of you" (i.e., like you, in your deeds). So that, perforce, we must understand it as: Just as Israel are accepters of the covenant, so, proselytes — to exclude heretics, who are not, having broken the covenant. And thus is it written (Mishlei 21:27): "The sacrifice of the wicked is an abomination."

4) "A man, if he offer, etc." I might think this is a decree (i.e., that he must do so), it is, therefore, written "if he offer" — it is optional. (Mishlei 21:27): "a sacrifice (korban) to the L–rd" — he must sanctify it (by saying "This is a burnt-offering") before offering it up, (thus rendering it a "korban" before he actually sacrifices it). These are the words of R. Yehudah. R. Shimon said: Whence is it derived that one should not say: "To the L–rd, a burnt-offering," "To the L–rd, a meal-offering," "To the L–rd, peace-offerings?" From "a sacrifice (korban) to the L–rd." Now is this not a kal vachomer? If in respect to what is destined to be sanctified, Scripture states that the name of Heaven is to be mentioned only after "korban" (to forestall the possibility of its being mentioned in vain by his saying "To the L–rd," and not following up with "korban") — how much more so must the name of Heaven not be mentioned in vain (in mundane circumstances)!

Another thing, a letter to David. David said, "I am a stain." This is similar to someone who was passing by and had two coins in his hand. He saw a certain inn, one of which served fish and the other served meat. He said, "What should I do if I tell him to bring me food?" Immediately, he brings me plates and I only have two coins. He went and said to the innkeeper, "Give me food for two coins." The innkeeper asked, "What will I give you for two coins?" He replied, "Haven't you heard what the parable teaches? 'According to my purse, I dance.' " Similarly, King David said, "I cannot sit with the great ones, I will wait with the little ones. Let Abraham, Isaac, and Jacob be in the small room, and Moses and Aaron be in the antechamber, and I will stand on the threshold (Psalms 131:1-2). I have chosen to huddle in the house of God. And if I cannot sit on the threshold, I will not leave the inn (ibid). Within the walls of Jerusalem, hallelujah. A prayer of David: "Hear, O Lord, my righteousness" (Psalms 17:1). This is as the scripture says (Proverbs 21:27), "The sacrifice of the wicked is an abomination." Rabbi Yehoshua said in the name of Rabbi Chanina, "Because Balaam said to Balak (Numbers 23:1), 'Build me here seven altars,' meaning that the Lord desires sacrifices. But He says to Job's friends (Job 42:8), 'Now take for yourselves seven bulls and seven rams.' The Lord said to them, 'I do not desire your sacrifices; the sacrifice of the wicked is an abomination to Me.' So what do I desire from the prayers of Israel? As it is said (Proverbs 15:8), 'The prayer of the upright is His delight.'