[53a top] Rebbe: One may not do Chalitza with a Tenei (condition) built into it (and if one did the Chalitzah would be valid even if the condition was not met). cuz we dont have power over it.
Tosephos [GM’ Kesuvas 74]: If one may not appoint an agent to do a specific activity for him/her, then one may also not make a condition on the act. This shows a reflection of a lack of Baylus (ownership) [no real control over the act but by doing so we are granted specific results].
R’ Rosner: IE: One may not make a condition upon donning Tefillin, that he only wants the Mitzvah to be fulfilled if it is snowing outside [of course he gets his Mitzvah regardless of the weather]. And similarly, he may also not appoint another man to put Tefillin on for him.
D-E-ep Thoughts: Hashem gives us “control” in many areas of our lives, but reminds us in various aspects of life and Halacha (Jewish law) that He is the One running the show.
“מענ טראַכט און גאָט לאַכט” (man plans and G-d laughs). We must remember that even when we act and choose, ultimately the will of G-d will come into fruition. We must always act and try our best in this world, but never be saddened or haughty because the end results are only brought into fruition by Hashem.