Musnad Ahmad 216:3

Sufyan ibn 'Uyaynah narrated to us, from Harun ibn Ri'ab, from Kinanah ibn Nu'aym, from Qabisah ibn al-Mukhariq al-Hilali, who said: I took upon myself a debt (hamalah), so I came to the Messenger of Allah, peace and blessings of Allah be upon him, to ask him about it. He said: "We shall pay it on your behalf, and we shall take it out from the livestock of the Zakat." And he said once: "And we shall take it out when the Zakat comes to us—or when the livestock of the Zakat comes." And he said: "O Qabisah, asking is not permissible." And he said once: "It is forbidden, except in three cases: A man who has taken upon himself a debt; asking is permissible for him until he pays it, then he must refrain. And a man who has been struck by need and poverty, until three men of sound judgment from his people testify for him." And he said once: "A man who has been struck by poverty—or need—until three men of sound judgment from his people testify for him—or speak—that he has been struck by need or poverty; then asking is permissible for him, so he may ask until he obtains a subsistence of life or a sufficiency of life, then he must refrain. And a man who has been struck by a calamity that has destroyed his wealth; asking is permissible for him, so he may ask until he obtains a subsistence of life or a sufficiency of life, then he must refrain. And whatever is other than that of asking is unlawful (suht)."