Hazrat Raafay Bin Amar who was with Hazrat Khaalid Bin Waleed says,

The condition was this, that we had become absolutely disappointed with our lives, and all of a sudden the voice of Takbeer [Allaahu Akbar, Allaah is the Greatest] was heard.

Hazrat Khaalid looked, from where did this voice came. When he looked towards the army of the Romans, then he saw that, some riders are following them, and they are running towards them senselessly, Khaalid reached close to a rider by racing the horse and inquired,

O you young man, who are you?

She replied,

I am your wife Umme Tameem, I have brought your sacred cap by the blessing of which you recieve victory on the enemies. You had forgotten this due to which this hardship had come on to you.

Anyhow, she gave that cap to him and Hazrat Khaalid wore it.

(Fatoohush-Shaam, pg.115, Dalaailun Nubuwwah Baiehaqee, vol-6, pg. 249)

Excerpt from the Book ‘Zikr e Jameel’ by Hazrat Maulana Muhammad Shafee Okarvi [Rahmatul Laah Alaieh]