Imam Sadiq (peace be upon him): Abu Amr al-Zubayri said: I said to Imam Sadiq (peace be upon him), "Faith has degrees and stations. Do the believers have superiority over one another in those stations before Allah?" He said, "Yes." I said, "May Allah have mercy on you, describe it to me so that I may understand." He said, "Allah places a race between the believers, just as horses are raced on the day of wagering. Then He gives them precedence according to their degrees in racing toward Him, and He grants each of them a degree according to his precedence, and nothing of his right is diminished, and no latecomer outstrips a forerunner, and no one of lesser degree outstrips one of greater degree. In this way the first and the last of this ummah are distinguished in terms of merit. If the forerunner in faith had no merit over the one who came later, then the last of this ummah would catch up with its first. Yes, if the forerunner in faith had no excellence over the one who delayed in accepting faith and came after him, the last of this ummah would surpass him. But Allah, by the degrees of faith, gave precedence to the forerunners, and because of their delay in faith He placed the negligent in the later ranks; for we find that the acts of worship of some of the later believers exceed those of the earlier ones — their prayer, fasting, hajj, zakat, jihad and spending are greater. If there were no criteria of precedence by which some believers surpass others in rank before Allah, the later ones by their abundant worship would have taken precedence over the earlier ones. But Allah, the Mighty and Majestic, refused to allow the first of the believers to hold the lowest degrees of faith, or that the one whom Allah has placed last should be advanced, or that the one whom Allah has advanced should be delayed." I said, "Inform me about the racing to faith to which Allah, the Mighty and Majestic, has summoned the believers." He said, "The words of Allah, the Mighty and Majestic: سَابِقُوا إِلی مَغْفِرَةٍ مِّن رَّبِّکُمْ وَجَنَّةٍ عَرْضُهَا کَعَرْضِ السَّمَاءِ وَالْأَرْضِ أُعِدَّتْ لِلَّذِینَ آمَنُوا بِاللهِ وَرُسُلِهِ [Hasten to forgiveness from your Lord and to a garden the extensiveness of which is as the extensiveness of the heaven and the earth; it is prepared for those who believe in Allah and His messengers]. And He said: وَالسَّابِقُونَ السَّابِقُونَ * أُولئِکَ الْمُقَرَّبُونَ [And the foremost are the foremost; those are the ones brought near]. And He said: 'And the forerunners, the first of the Emigrants and the Helpers, and those who followed them in doing good — Allah is pleased with them and they are pleased with Him' (al-Tawbah 9:100). He began with the first Emigrants because of the degree of their precedence, then he mentioned in the second rank the Helpers, and in the third rank those who followed them in doing good. So He placed each group according to the measure of their degrees and stations before their Lord. Then He mentioned the factor by which Allah, the Mighty and Majestic, granted some of His friends superiority over others. Allah, the Mighty and Majestic, said: 'We have made some of these messengers to excel others; some of them there are to whom Allah spoke, and some of them He raised in rank. And We gave Isa son of Maryam clear proofs and strengthened him with the Holy Spirit. If Allah had willed, those after them would not have fought one another after clear proofs had come to them, but they differed. So some of them believed and some of them disbelieved. And if Allah had willed, they would not have fought one another, but Allah does what He wills' (al-Baqarah 2:253). And He said: 'And indeed We have made some of the prophets excel over others' (al-Isra 17:55). And He said: 'See how We have made some of them excel over others, and indeed the Hereafter is greater in degrees and greater in excellence' (al-Isra 17:21). And He said: 'They are in [varying] degrees before Allah' (Al Imran 3:163). And He said: 'And He will grant every possessor of merit his merit' (Hud 11:3). And He said: 'Those who believed and emigrated and struggled in the way of Allah with their wealth and their lives are greater in rank before Allah' (al-Tawbah 9:20). And He said: 'Allah has given the mujahidin a great reward above those who sit [at home] — degrees from Him, and forgiveness, and mercy' (al-Nisa 4:95–96). And He said: 'Not equal among you are those who spent and fought before the conquest [of Makkah]; those are greater in rank than those who spent and fought afterwards' (al-Hadid 57:10). And He said: 'Allah will raise those of you who believe and those given knowledge in degrees' (al-Mujadalah 58:11). And He said: 'That is because they suffer no thirst, no fatigue, no hunger in the way of Allah, and they tread no place that enrages the disbelievers, nor gain any gain from the enemy, but that a righteous deed is written for them by it' (al-Tawbah 9:120 [Persian cites 9:11]). And He said: 'And whatever good you send forward for yourselves, you will find it with Allah' (al-Baqarah 2:110). And He said: 'So whoever does an atom's weight of good will see it, and whoever does an atom's weight of evil will see it' (al-Zalzalah 99:7–8). These verses set forth the degrees and stations of faith before Allah, the Mighty and Majestic."