Sefer Ha’mitzvos Ha’Katzar (The concise book of mitzvos) By the Chofetz Chaim
This book lists the Torah mitzvos that can be observed today
Second Section – the Negative Commandments
56. It is a negative commandment “do not refrain from lending to another Jew due to fear that the Shmittah year (seventh year) is nearby and the loan will be cancelled”
As it states in Devarim (Deuteronomy) 15:9, “Guard yourself lest you think in your heart saying the seventh year, the Shmittah year, is approaching, and your eye does evil.” This is a great sin, as the Torah calls him a miscreant.
This applies to men and to women according to Torah law during times when there was a Yovel year, but nowadays it is a Rabbinic commandment. The Rabenu Yona writes: At a time he will not lose his loan, how much greater of a sin is it if he hardens his heart not to extend a loan.