The answer to "what is partial" in 1 Cor 13:10 is found in 1 Cor 13:9 -
9 For we know in part and we prophesy in part, 10 but when the perfect comes, the partial will pass away.
That is, the partial refers to incomplete and imperfect knowledge/prophecy. As the Cambridge commentary succinctly observes:
- and we prophesy in part All inspired utterances are but partial revelations of Divine Truth.
Similarly, Poole observes:
For we know in part; it was truly said, as to things human, that the greatest part of those things that we know, is the least part of
those things which we are ignorant of. A great measure of Divine
things is also unknown to us, and the knowledge of them reserved for
thr resurrection and day of judgment, John 14:20.
And we prophesy in part; nor can the communication of our knowledge to that, be larger than what we by prophecy communicate; we
having ourselves but a short and imperfect communication of Divine
things, we can communicate but an imperfect degree of knowledge to
While ever we are still human and have imperfect human minds and bodies (as distinct from the heavenly bodies promised in 1 Cor 15:39-51), nothing can be complete or perfect. We have imperfect knowledge, imperfect/incomplete revelation of God, imperfect/partial understanding of spiritual things, etc, etc.