Can I influence Mitzvot retroactively?

Question

I heard that you can retroactively influence the Mitzvot you already did. For example, let's say I put on Tefilin everyday, but, in one specific day, I felt really sick and I have to make a really big effort to also put on Tefilin that day. If I do manage to do it that day, it shows that I was ready to make this kind of effort and I would do the Mitzvá even in difficult situations.

I heard that the merit I had putting on Tefilin on a normal day will be increased after this situation, because H'shem will recognize that I would be willing to do the Mitzvá even if it was hard for me and involved effort. This way I proved that I don't put the Tefilin just because it is easy, but because I take it really seriously. Being so, I deserve, retroactively, to earn more merit for all those regular Tefilin days.

It this correct? If so, could anyone tell me the source?

Answer 1

Regarding your observation/question, "Hashem will recognize that I would be willing to do the Mitzvah even if it was hard for me and involved effort. " I would like to point out a commentary by Rabbi Dovid ben Shalom HaKohen, author of Ohr Dovid.

In the sefer, he writes that, let's say a person is suffering because he cannot fulfill certain mitzvos, either because he's sick or other reasons, but he really wants to observe those mitzvos in his heart, scripture regards him as if he did them. See: "אור דוד"

או אחרת מעלה עליו הכתוב כאילו עשאה וכן אמרו חז"ל הלומד זבחים ומנחות או האומר סדר הקרבנות מעלה עליו הכתוב כאילו הקריבן וכן אמרו מחשבה טובה הקדוש ברוך הוא מצרפה למעשה כל שכן אם זו לא רק מחשבה אלא גם הבעה של צער על חוסר האפשרות לקיימה הרי בודאי שהקדוש ברוך הוא מחשיב גם את המחשבה וגם את הרצון למעשה

There are different mitzvot in Eretz Yisrael, the author of Or David writes:

יש מצוות השייכות למלך ויש לכהנים ויש לבכורים וכו' There are mitzvot that belong to the king, priests and firstborns

So, when Moshe Rabbeinu asked G-d to fulfill (all) those mitzvot, G-d saw that Moshe Rabbeinu really wanted to fulfill them all, and to this applies the statement of the Or David. Namely, that in this case, scripture raises this person as if he fulfilled them all.

Taken from my answere at this post.