The Prophet, peace and blessings be upon him, said, “The shade of the believer on the Day of Resurrection is his charity.”
Source: Musnad Aḥmad 23490
Sadaqah comes from the root word sidq which means sincerity.
it is an indication of sincerity of imaan (faith) and confirms ones sincere devotion to Allah alone.
Those who spend their wealth in the cause of Allah and do not follow their charity with reminders of their generosity or hurtful words – they will get their reward from their Lord, and there will be no fear for them, nor will they grieve.
Holy Qur’an, al-Baqarah 262