Hazrat ‘Abdur Rahmaan bin ‘Auf (radhiyallahu ‘anhu) reports that Hazrat ‘Uthmaan (radhiyallahu ‘anhu) contributed seven hundred ooqiyah of gold for the expedition of Tabook. In another narration, it is mentioned that Hazrat ‘Uthmaan (radhiyallahu ‘anhu) contributed seven hundred and fifty camels and fifty horses for the expedition of Tabook.
(Siyar A’laam min Nubalaa 2/152)
Mulla ‘Ali Qaari (rahimahullah) has mentioned that Hazrat ‘Uthmaan (radhiyallahu ‘anhu) had made multiple contributions for the expedition of Tabook. Hence, this Hadith will not go against the Hadith which mentions that he had equipped the army with six hundred camels.
(Mirqaat 17/399)
Hazrat Abu Hurairah (radhiyallahu ‘anhu) mentioned, “Hazrat ‘Uthmaan (radhiyallahu ‘anhu) purchased Jannah from Rasulullah (sallallahu ‘alaihi wasallam) on two occasions; when he purchased the well of Roomah, and when he equipped the expedition of Tabook.”
(Siyar A’laam min Nubalaa 2/153)