How did Imam Hassan (AS) reciprocate a good deed?

Anas ibn Malik narrated: One of the maids gifted a flower to Imam Hassan (AS). Imam Hassan (AS) took the flower and told her: I will set you free for the sake of Allah (SWT). Anas asked Imam Hassan (AS): Did you set her free for the sake just one flower? Imam Hassan (AS) replied: Allah (SWT) has educated us the same way in the Quran, when in Ayah 86 of Surah Al-Nesa, God said: “When a person greets you, answer back with a better way or at least the same way”, I wanted to give a better answer which was to free her [1].

[1] Beharul Anwaar, Vol. 43, Page 343.