تَعْلَمُ مَا فِي نَفْسِي وَلَا أَعْلَمُ مَا فِي نَفْسِكَ
You know what is within me, while I do not know what is known to You.
The first nafs is related to Jesus's own person and inward state. The second occurrence corresponds verbally to the first, but it does not attribute creaturely bodily or psychological conditions to God. The passage contrasts God's complete knowledge with the servant's limited knowledge.
The relevance of mushākalah is precisely that repetition of a lexical form need not entail identical referential or theological implications in both occurrences.