When I read St. Isaac the Syrian, I am at the same time inspired by how clearly he seems to be reading my thoughts and advising me, and I am also blown away by how extreme his advice is.
It helps to keep in mind that St. Isaac is writing for hermits, not married folk in the world; nevertheless, St. Isaac speaks to me.
It is somewhat like being guided by a star. The star itself is virtually unattainable given my calling and circumstances in life, yet the star can guide me even from afar. It can help me know which is the right direction as I take my baby steps in the spiritual path.
I think it would be a mistake to dismiss St. Isaac’s teaching as unattainable and therefore irrelevant. In fact, I think the opposite is true. St. Isaac is one of the most relevant Fathers for the serious Christian to read today. But he must be read carefully, ideally with the guidance of a spiritual father or mother. St. Isaac is a star in the heavens, and his writings light up the sky; but they are very lofty, and if read without care could lead either to delusion or despondency.
However, if read as a bright and distant star, a star giving its full light to the few planets (hermits) in near orbit, but giving a clear pinpoint of guiding help to those very far away, if St. Isaac is read in this way, then he can be a great help, encouraging and guiding those spiritual harlots like me who still long to search out spiritual things and long to offer prayers with boldness.