لَا نَحْكُمُ بِالنِّسْبَةِ الْيَوْمَ؛ فَالْعِلْمُ أَمَانَةٌ.
We do not decide the attribution today, for knowledge is a trust.
Al-ʿilmu amānatun is an independent maxim extending the particular decision into a general norm. This supports an analysis as tadhyīl, while the connecting fāʾ can also give the maxim the force of justification. The two functions are compatible when each is independently supported by context.
Delaying attribution concerns one specific document; the trustworthiness of scholarship is a broader principle. A mere synonymous repetition of the initial sentence would not carry the same generalizing rhetorical effect.