ביצים א

The essential sign of purity is the scales — for every fish that has scales also has fins, while fins alone are no sign at all, for some fish have fins but no scales.

And so too the borrower, who has been obligated to the lender through having received money from him, is in the aspect of his nefesh, as above. And through the obligating of the borrower himself, through this all the possessions of the borrower automatically become obligated to the lender — for all possessions are in the aspect of nefesh, as above. And since the lender has acquired the nefesh of the borrower for all the days of the duration of the loan, it follows that he takes from the borrower great reward on account of the waiting with the money — that is, the flow of abundance of money which the lender receives from the aspect of the nefesh of the borrower — for every nefesh has its flow of abundance of money, as is explained in the words of our Rebbe, may his memory be a blessing, there, see there. Therefore it is forbidden to take additional interest from him — for he has already received great reward all the days of the loan, namely the flow of abundance of money that he received from the nefesh of the borrower, as above. And therefore its prohibition is exceedingly severe, for in this prohibition the Sitra Achra gains its greatest hold — for the borrower is called ba'al chov (a debtor), which is the aspect of idolatry (avodah zarah), which is called chovah — as is found in the words of our Rebbe, may his light shine, in §23. And therefore a person must guard himself very greatly from being a ba'al chov (one who carries debt), and in any case the loan must be made in a permitted manner according to the Torah. But when a prohibition is created in the loan — that is, the prohibition of ribbis — then the Sitra Achra, which is the aspect of chovah, the aspect of idolatry, as above, gains a very strong foothold there — for it has a hold there, as above.

And therefore it is counted as if he denies — which is the aspect of idolatry — for in truth one must believe that all abundance flows only from the Blessed One. And when one believes that the abundance of money comes from above, certainly he will not take ribbis from the borrower — for he has already received a great deal from the borrower from the aspect of his nefesh, as above.

And because he was not careful in this and left Agag king of Amalek alive, therefore his kingdom was cut off. For the essential sustaining of Malchus depends on wiping out Amalek, as mentioned. And this is what Shmuel said: "Osi shalach Hashem limashchacha l'melech al Yisrael v'atah lech v'hikisa es Amalek" etc. ("Hashem sent me to anoint you as king over Israel — now go and smite Amalek"). For one depends on the other — since you have been anointed as king over Israel, you must wipe out the memory of Amalek, as mentioned.