And know further that he must be very careful not to counsel Reuven to enter into partnership with Shimon if he knows of any loss that might result from their partnership (as when Shimon is very poor; how much more so, if he is not trustworthy). The same applies to [seeking] a match [shidduch] or a craftsman or the like. For even in the instances in which it is forbidden to go and speak rechiluth against Shimon, such as going and saying against him before Reuven, that he is in straitened circumstances, as mentioned above (and, likewise, in respect to a shidduch or a craftsman, each in its own way), it is forbidden to do so only by harming Shimon —

but the opposite; that is, to harm Reuven and to counsel him to enter into partnership or into a shidduch with Shimon, and the like — if he [Ploni] knew in himself that if he were in the same position [as Reuven], as when he required the same things, he would distance himself from such people in Shimon's circumstances] — it is an absolute issur to counsel Reuven in this [direction], it being in the category of "You shall not place a stumbling block before the blind," of which Chazal have said: "Do not give him counsel which is inappropriate for him." And there are people who stumble in this because of their self-interest. This is a grave sin, money-lust causing them to transgress a negative commandment of the Torah.