Musnad Ahmad 1272:9

Hassan narrated to us, he said: Ibn Lahi'ah narrated to us, he said: Abu al-Aswad Muhammad ibn Abd al-Rahman ibn Nawfal narrated to us, that he heard Durrah bint Mu'adh narrating from Umm Hani, that she asked the Messenger of Allah, peace and blessings of Allah be upon him: "Shall we visit one another when we die, and shall some of us see others?" The Messenger of Allah, peace and blessings of Allah be upon him, said: "The souls (nusam) will be birds hanging from the trees, until, when the Day of Resurrection comes, every soul will enter into its body."