Is a person obligated in a Mitzvah that he can only fulfill with assistance?

Question

If a person is unable to perform a Mitzvah on his own - like putting on Tefillin, or holding/shaking the Lulav etc. - is there still a full fledged obligation for him to go through every kind of trouble in order to get assistance?

Answer 1

The Pele Yoetz explains that the way to determine if a situation is an ones or not is to think if he was able to make a lot of money doing this, would he still say that he can’t because of the situation. If so, he is patur, otherwise he should overcome the obstacle and do it anyway:

וכדי להבחין מה הוא אנס גמור ומה הוא שאינו חשוב אנס, ידמה שאלו היה מוצא להרויח הון עתק, אם מחמת אנס כזה היה מכרח להניח מלהרויח אז הוא אנס גמור, ואם להרויח ממון אינו משגיח בזה האנס ודוחק את עצמו באמרו, מה לעשות רוח יש כאן, צריך לדחק מה יענה ליום פקדה, הלוא יבוש ויכלם, ולא יהיה לו פה להשיב ולא מצח להרים ראש, וענוש יענש כאשר ישית עליו בעל המשפט. על זה נאמר (משלי ב ד, ה): אם תבקשנה ככסף וכמטמנים תחפשנה אז תבין יראת ה'. זה כלל גדול בתורה, כי סחרה ליהודים היתה אורה

Answer 2

Perhaps we can suggest an answer from the halachah that if someone is missing his arms, he must still put on tefillin shel rosh. Such a person must require significant help from others, but is still commanded. (Check my source, I could be misunderstanding this!! Although I've heard this halachah taught this way before, I haven't been able to find a source that's as definitive as I'd like.)

This halachah is near the beginning of Orach Chaim 27, but note that it doesn't say it very clearly, only by omission.

Here's the source from Shulchan Aruch Harav, which is I think a little clearer in this case than the equivalent Rama.

https://www.chabad.org/library/article_cdo/aid/3284473/jewish/Shulchan-Aruch-Chapter-27-Laws-Relating-to-Place-and-Manner-in-which-Tefillin-are-Put-On.htm#v3

Note that in the regular Shulchan Aruch, the dispute the Rama cites is only based on something specific to tefillin, as the Magen Avraham relates at length.