Hawzah News Agency – Imam al-Sadiq peace be upon him says:

إنّ الإيمانَ عَشْرُ دَرَجاتٍ بِمَنزِلَةِ السُلَّمِ، يُصْعَدُ مِنهُ مِرْقاةً بَعدَ مِرْقاةٍ، فلا يَقُولَنَّ صاحبُ الاثنَينِ لِصاحِبِ الواحدِ: لَستَ على‏ شَي‏ءٍ، حتّى‏ يَنْتهيَ إلَى العاشِرِ. فلا تُسْقِطْ مَن هُو دُونَكَ فيُسْقِطَكَ مَن هُو فَوقَكَ، وإذا رأيتَ مَن هُو أسْفَلُ مِنكَ بدرجةٍ فارْفَعْهُ إليكَ برِفْقٍ، ولا تَحْمِلَنَّ علَيهِ ما لا يُطيقُ فَتَكْسِرَهُ، فإنّ مَن كَسَرَ مؤمناً فعلَيهِ جَبْرُهُ.

'Certainly faith is ten levels, like the rungs of a ladder, where each rung is climbed one after the other. The one on the second rung cannot say to the one on the first: 'You are nothing' until he completes the ten. Therefore, do not knock the one below you down, lest the one above you knocks you down. And when you see one below you in rank, lift him up to your level with gentleness. And do not burden him with that which he cannot bear lest you break him, for verily one who breaks a believer must put him back together again.'

Source: al-Kafi, v. 2, p. 45, no. 2