A single individual cannot be expected to carry out all the 613 mitzvot.
There are those that concern only a man or a woman, a priest or a king.
Nevertheless, a person can perform them as part of the whole of Israel, as an integral component of a particular generation in time and place.
For every generation is a cross section of the timeless entity which is Israel.
And even if a person cannot carry out a mitzvah in terms of action, he can perform it in speech and in thought.
By reading aloud and studying Torah, all the 613 mitzvot find their expression in the individual whose soul, in turn, finds therein its Tikun or correction.
As this suggests, there are many levels of uniting with Torah, depending on one's capacities.
There are those who are limited by their intellects, others by their willpower or their soul roots.
That is to say, a person can comprehend something in Scripture and yet be unable to make contact with it somehow,because the root of his soul shrinks from it.
All men are conscious of an attraction to certain aspects of Torah and an incapacity to react to others.
There is the well-known anecdote about Rabbi Joseph Karo, one of the greatest thinkers and Kabbalists in Jewish history, who used to fall asleep at the lessons with the Ari, until the latter finally told him that this was not his way.
In other words, the root of his soul was not attuned to the Kabbalah of the Ari.
To be sure, this is a common discrepancy, just as there have been instances of persons of poorly endowed intellect who were able to grasp the intricacies of the Ari with ease.
Every person seems to have his own preference or talent.
It is hardly even a matter of intelligence; it is more a function of the root of the soul which facilitates a direct communication with a certain subject or mode of expression in the Torah.
In terms of Halachah, where the doing is important, such a gap between intellectual grasp and emotional identification becomes more obviously a problem.
Chasidism is full of stories of the need of the soul for wholeness.
–Rabbi Adin Steinsaltz
From The Long Shorter Way, "The Garments of the Soul," by Rabbi Adin Steinsaltz