The following is a freely-translated excerpt from a letter by the Rebbe
written in the opening days of the year 5732 (September, 1971):
A question:
As we know and see, there are situations in which Jews, regardless of their
best intentions, regardless, even, of their self-sacrifice, are truly unable to
fulfill the will of G-d due to circumstances beyond their control. As the
parable goes, self-sacrifice can enable one to jump off a roof down to the
ground, but it cannot enable one to jump from the ground up onto the roof...
But G-d is the master of the entire world. Since G-d Himself has commanded
and spelled out how every Jew should behave in his daily life, how is it
possible that there should be a situation in which a Jew is unable to carry out
the will of G-d, in every detail?
The answer:
There are two components to a mitzvah: the deed, and the kavanah and
feeling that accompany it. It is true that “the deed is the primary thing,”
but the kavanah and feeling are also of great importance.
When it happens that there is a situation in which it is impossible for a Jew
to actually carry out the will of G-d despite his self-sacrifice, this
stimulates in him a deep spiritual pain that pervades him to the very core of
his soul, bringing him to a deeper connection with G-d, and with Torah, mitzvot
and his Jewishness, the likes of which he could never have attained without this
painful experience.
The fact that he did not actually do the mitzvah has no adverse effect
on his relationship with G-d, since he was prevented from doing it by forces
beyond his control. On the other hand, the feeling element of the mitzvah
achieves a height otherwise unobtainable, and the experience imparts to his
spiritual life a depth and perfection that only this situation can generate.