No one of those who took the oath of allegiance under the tree will go to hell.
Sunan Abi Dawud Book 42, Hadith 58
← Previous Hadith The Prophet (ﷺ) said: Gabriel came and taking me by the hand showed the gate of Paradise by which my people will enter. AbuBakr then said: Messenger of Allah! I wish I had been with you so that I might have looked at it. The Messenger of Allah (ﷺ) then said: You, AbuBakr, will be the first of my people to enter Paradise.

Sunan Abi Dawud Book 42, Hadith 57 Next Hadith → Perhaps Allah, and Ibn Sinan’s version has : Allah looked at the participants of the battle of Badr (with mercy) and said : Do whatever you wish ; I have forgiven you.

Sunan Abi Dawud Book 42, Hadith 59