This is from the Ohr Someyach, Hilchos Talmud Torah.
The difference may be subtle, but it can have an enormous effect on your attitude towards your obligations – If we realize that our personal difficulties with our obligations will not only be taken into account at Judgement Day, but that Hashem originally, in the Torah, only asked of me what He feels I can do today, we would act differently.
This, he says, is the meaning of the passuk in this weeks parshah (18,20)- “v’hizharta osam etc”, and afterwards “v’hodata etc” – first the chukim and toros, thats equal for everyone, then the “derech” they should go on, and the “ma’aseh” they should do – thats a separate part of the passuk, because that’s according to the individual.