LEV1063 There are usually numerous people involved in any business deal or loan transaction. If interest is charged in the loan, Jewish law is violated [Exodus 22:24 and this verse]. Therefore, in such a business loan, says the Talmud, not only has the actual loaner sinned, but all the parties involved have as well, including the guarantors, witnesses, and scribes, and all have violated "placing a stumbling block" by enabling the sin of interest being charged. Tosafot (Tosafot commentary, "Minayin" on Avodah Zarah 6b) says that this prohibition against enabling a sin applies to all sins in the Torah, not only the ones cited in the Talmud. By actively helping or enabling any person to sin, you violate the Torah prohibition of "placing a stumbling block," even when the sinner is clearly aware of this sin. Certainly, any inciter or initiator of sin, even with the full knowledge of the sinner, would also violate this prohibition.