How should the Hadith regarding Abu Bakr's gift be interpreted in relation to the requirement of possession?

Primary text

The Hadith concerning Abu Bakr's gift of twenty sa's of gathered dates (jadhadh) is not necessarily binding without possession. It is likely referring to twenty sa's of gathered dates that are measurable but unspecified, which necessitates receipt. Alternatively, if it refers to dates to be gathered from palms yielding twenty sa's, it is also unspecified, and the gift before specification is invalid, meaning it implies a promise of a gift (wahba).