Aban ibn Taghlib, one of the close companions and students of Imam Sadiq (a.s.), narrates:
“I was performing Tawaf around the Kaaba with Imam Sadiq (a.s.) when one of the Shia approached and asked me to accompany him somewhere to help with a problem he was facing. At that moment, I was deeply enjoying my Tawaf and the company of Imam Sadiq (a.s.), so I was reluctant to leave. The man repeated his request several times with hand gestures, until Imam Sadiq (a.s.) noticed him and asked me, ‘Does this man need something from you?’
I replied, ‘Yes, he does.’ The Imam asked, ‘Then why don’t you go to him?’
I said, ‘Do you mean to say I should break my Tawaf?’ The Imam responded, ‘Yes.’
I asked again, ‘Even if my Tawaf is obligatory?’ The Imam said, ‘Yes, break your Tawaf and go see what he needs.’
Aban continues: So, I left the Tawaf and went with the needy Shia, helped him solve his problem, and then returned to Imam Sadiq (a.s.). When I came back, I asked the Imam, ‘I would like to know, what is the right of a believer upon another believer?’
The Imam replied, ‘O Aban, do not ask this question (for the answer is very heavy and burdensome, and you may not be able to bear it).’
I insisted, ‘May I be your ransom, please tell me!’ After repeating my request a few times, the Imam finally said, ‘O Aban, are you willing to give half of your wealth to that needy person?’
When the Imam saw the change in my expression, he said, ‘O Aban, don’t you know that Allah praises the selfless believers who prefer others over themselves, as mentioned in the verse: “«وَيُؤْثِرُونَ عَلَىٰ أَنفُسِهِمْ وَلَوْ كَانَ بِهِمْ خَصَاصَةٌ» “[1]
Aban said: I replied, ‘Yes, indeed Allah has said this.’
Then the Imam continued, ‘O Aban, know that if you give half of your wealth to him, you have merely treated him equally, not preferred him over yourself. You will have truly practiced selflessness (and be among those praised by Allah in the verse) when you give something from the remaining half of your wealth as well, until his wealth surpasses yours.’
[1] . “They give others preference over themselves, even though they are themselves in need.”
(Surah Al-Hashr, 59:9)