It is mentioned in Manaqib Ibne Shahr Ashob that some people
have narrated from Khalid bin Walid that:
I saw Ali Ibne Abi Talib (a.s.) repairing the links of his coat of mail with his bare hands.
I asked: Softening of the iron was for Dawood (a.s.)?
His Eminence replied: “It was due to us that Almighty Allah softened iron for His Eminence Dawood (a.s.).
[Don’t you think] what our position should be?!”
It is mentioned in another report that he wrapped the iron sword
around the neck of Khalid (Mustadrak Safeena, vol. 2,)
Isbaatul Wilayah (Part One) – Ayatullah AliNamazi Shahroodi (r.a.)