Answered by Sayyidi al-Ḥabīb `Umar bin Hafīẓ (may Allāh preserve him and benefit us by him).
I fear that your purification lessons are a proof against me as they carry great benefit and I do not act upon them as I should. For this reason I feel that I should cease following them.
You should continue to follow these lessons and along while intending to act upon them to the extent that you are able to, even if it is a little.
You considering yourself incapable and deficient is in itself a manifestation of acting upon the knowledge. However, along with this, we should have a resolve to act upon what we learn and fulfil some of these obligations. In addition to following these lessons, reading beneficial books and seeking beneficial knowledge, we should teach those that we can, and not refrain from this because we do not act on what we know – and at the same time we should force ourselves to practise even a little of what we learn.
The threat (mentioned in the Qur’ān and the Sunnah) of such things being considered a proof against you is directed to those who are content not to act upon what they know. It is not directed at those who reproach themselves and take themselves to account for not acting.