Abu Talha was shooting arrows in front of the Messenger of Allah ﷺ, and the Messenger of Allah ﷺ was raising his head from behind him to see where his arrows were landing. Abu Talha stretched out his chest to shield the Messenger of Allah ﷺ with it and said, "Messenger of Allah, let my chest take what would strike yours."
حدثنا ابن أبي عدي عن حميد
كان أبو طلحة يرمي بين يدي رسول الله ﷺ وكان رسول الله ﷺ يرفع رأسه من خلفه لينظر إلى مواقع نبله قال فتطاول أبو طلحة بصدره يقي به رسول الله ﷺ وقال يا رسول الله نحري دون نحرك
Its chain of transmission is sahih, Bukhari related it 7/128 no. 3811 Fath, in Merits of the Ansar, Merits of Abu Talha, and Muslim 3/1443 no. 1811, in Jihad, Women Fighting Alongside Men.