In Muslim, this Hadith is narrated by 'Aishah (May Allah be pleased with her), and in both these narrations Ibn Wahb has said that the meaning of Muhaddithun is recipients of Divine inspiration.
Commentary: "Mulhamun" [persons endowed with inspiration]; in other words, things are put in their hearts by Allah, it was done in the case of the mother of Prophet Musa. It was put in her mind by Allah that if she felt any fear, she should then trust the child to the sea. Maryam (Mary) also used to receive inspiration, which is also a form of marvel. This Hadith evidently shows the distinction of 'Umar (May Allah be pleased with him).