5 The Lord is the portion of my possession and my cup⁹; you make my future secure. 6 It is as if I have been given fertile fields or received a beautiful tract of land. 7 I will praise the Lord who guides me; yes, during the night my kidneys instruct me¹⁵. 8 I set the Lord before me continually¹⁶; because he is at my right hand, I will not be shaken. 9 So my heart rejoices and I am happy; my life is safe.

Rav said: The evil inclination is like a fly and it sits between the two entrances of the heart, as it is stated: “Dead flies make the ointment of the perfumer fetid and putrid” (Ecclesiastes 10:1). And Shmuel said: The evil inclination is like a type of wheat, as it is stated: “Transgression [ḥatat] couches at the door” (Genesis 4:7); ḥatat is interpreted homiletically as related to ḥitta, wheat. The Sages taught in a baraita: A person has two kidneys; one advises him to do good and one advises him to do evil. And it stands to reason that the one advising him to do good is to his right and the one that advises him to do evil is to his left, as it is written: “A wise man’s understanding is at his right hand, but a fool’s understanding is at his left” (Ecclesiastes 10:2). Tangential to the subject of kidneys, the Gemara cites that which the Sages taught in a baraita with regard to the roles of various organs: The kidneys advise, the heart understands, the tongue shapes the sounds that emerges from the mouth, the mouth completes the shaping of the voice, the esophagus takes in and lets out all kinds of food, the trachea produces the voice,