The Baal Shem Tov insisted that when you do a favor for another, there must be no strings attached and no expectations.

Of course, you want this person to become a better person, a more spiritual person, to fulfill the purpose for which this soul came to earth by learning Torah and doing mitzvahs.

And of course doing someone a favor is the best way to get that happening.

But when you do a favor, it has to be just for the sake of doing a favor. Unconditional love.

And that is the only way that love can have its effect.

—Likutei Sichot, vol.1, pg. 261. Ibid vol. 17, pg. 222.