Hadith 1:

Narrated that Imam Ridha (عليه السلام) said as part of a narration:

ومن كنا شفعاؤه نجى ولو كان عليه مثل وزر الثقلين الجن والإنس

"Whoever has Us as their intercessor will be saved, even if he has sins equal to that of the two heavyweights - the Jinn and mankind."

[Source: al-Faqih, Shaikh Saduq, Vol. 2, Pg. 585]

Hadith 2:

خَبَرٌ آخَرُ رُوِيَ عَنِ الْإِمَامِ الصَّادِقِ ع‌ أَنَّهُ كَانَ جَالِساً فِي الْحَرَمِ فِي مَقَامِ إِبْرَاهِيمَ ع فَجَاءَهُ رَجُلٌ شَيْخٌ كَبِيرٌ قَدْ فَنِيَ عُمُرُهُ فِي الْمَعْصِيَةِ فَنَظَرَ إِلَى الصَّادِقِ ع فَقَالَ نِعْمَ الشَّفِيعُ إِلَى اللَّهِ لِلْمُذْنِبِينَ ثُمَّ أَخَذَ بِأَسْتَارِ الْكَعْبَةِ وَ أَنْشَأَ يَقُولُ‌

بِحَقِّ جِلَاءِ وَجْهِكَ يَا وَلِيِّي‌ , بِحَقِّ الْهَاشِمِيِّ الْأَبْطَحِيِ‌

بِحَقِّ الذِّكْرِ إِذْ يُوحَى إِلَيْهِ‌ , بِحَقِّ وَصِيِّهِ الْبَطَلِ الْكَمِيِ‌

بِحَقِّ أَئِمَّةٍ سَلَفُوا جَمِيعاً , عَلَى مِنْهَاجِ جَدِّهِمُ النَّبِيِ‌

بِحَقِّ الْقَائِمِ الْمَهْدِيِّ إِلَّا , غَفَرْتَ خَطِيئَةَ الْعَبْدِ الْمُسِي‌ءِ

قَالَ فَسَمِعَ هَاتِفاً يَقُولُ يَا شَيْخُ كَانَ ذَنْبُكَ عَظِيماً وَ لَكِنْ غَفَرْنَا لَكَ جَمِيعَ ذُنُوبَكَ لِحُرْمَةِ شُفَعَائِكَ فَلَوْ سَأَلْتَنَا ذُنُوبَ أَهْلِ الْأَرْضِ لَغَفَرْنَا لَهُمْ غَيْرَ عَاقِرِ النَّاقَةِ وَ قَتَلَةِ الْأَنْبِيَاءِ وَ الْأَئِمَّةِ الطَّاهِرِينَ.

Narrated that once Imam Sadiq (عليه السلام) was sitting in the Haram (Holy Kaba) at the station (maqam) of Abraham (ع), when an old man came to him. The man had spent his entire life in disobedience. He looked at Imam al-Sadiq (عليه السلام) and said, "Great intercessor to Allah for the sinners!" Then he took hold of the curtains of the Kaaba and began to recite the following poem:

By the right of the radiance of Your face, O my Master,

By the right of the Hashemite al-Abtahee (resident of Mecca, i.e. Prophet Muhammad ص)

By the right of the Remembrance (Zekr) when it is revealed to Him,

By the right of His Successor, the hero/champion, and the brave,

By the right of all the Imams who have preceded on the path of their grandfather the Prophet (ص),

By the right of the Qaim al-Mahdi (عليه السلام) - You forgive the sin of the sinful servant.

He said, "Then he heard a voice calling, 'O old man, your sin was great, but We have forgiven you all your sins due to the respect/esteem (Hurmat) of your intercessors. If you had asked Us for the sins of the people of the earth, We would have forgiven them, except for the one who killed the she-camel (of Prophet Saleh), and the killers of the Prophets and the pure Imams."

[Source: al-Fazail, Shazan bin Jibrael al-Qummi, Pg. 66]

Hadith 3: The Prophet (ص) rewards on the day of Judgement

وَ قَالَ اَلصَّادِقُ عَلَيْهِ اَلسَّلاَمُ : «إِذَا كَانَ يَوْمُ اَلْقِيَامَةِ نَادَى مُنَادٍ أَيُّهَا اَلْخَلاَئِقُ أَنْصِتُوا فَإِنَّ مُحَمَّداً يُكَلِّمُكُمْ فَتُنْصِتُ اَلْخَلاَئِقُ فَيَقُومُ اَلنَّبِيُّ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ فَيَقُولُ «يَا مَعْشَرَ اَلْخَلاَئِقِ مَنْ كَانَتْ لَهُ عِنْدِي يَدٌ أَوْ مِنَّةٌ أَوْ مَعْرُوفٌ فَلْيَقُمْ حَتَّى أُكَافِيَهُ» فَيَقُولُونَ بِآبَائِنَا وَ أُمَّهَاتِنَا وَ أَيُّ يَدٍ وَ أَيُّ مِنَّةٍ وَ أَيُّ مَعْرُوفٍ لَنَا بَلِ اَلْيَدُ وَ اَلْمِنَّةُ وَ اَلْمَعْرُوفُ لِلَّهِ وَ لِرَسُولِهِ عَلَى جَمِيعِ اَلْخَلاَئِقِ فَيَقُولُ لَهُمْ «بَلَى مَنْ آوَى أَحَداً مِنْ أَهْلِ بَيْتِي أَوْ بَرَّهُمْ أَوْ كَسَاهُمْ مِنْ عُرْيٍ أَوْ أَشْبَعَ جَائِعَهُمْ فَلْيَقُمْ حَتَّى أُكَافِيَهُ» فَيَقُومُ أُنَاسٌ قَدْ فَعَلُوا ذَلِكَ فَيَأْتِي اَلنِّدَاءُ مِنْ عِنْدِ اَللَّهِ عَزَّ وَ جَلَّ «يَا مُحَمَّدُ يَا حَبِيبِي قَدْ جَعَلْتُ مُكَافَأَتَهُمْ إِلَيْكَ فَأَسْكِنْهُمْ مِنَ اَلْجَنَّةِ حَيْثُ شِئْتَ» قَالَ فَيُسْكِنُهُمْ فِي اَلْوَسِيلَةِ حَيْثُ لاَ يُحْجَبُونَ عَنْ مُحَمَّدٍ وَ أَهْلِ بَيْتِهِ صَلَوَاتُ اَللَّهِ عَلَيْهِمْ أَجْمَعِينَ ». 

Narrated that Imam Jafar ibn Muhammad al-Sadiq (عليه السلام) said:

"When it is the Day of Judgment, a caller will announce, 'O creation, remain silent, for Muhammad (صلى الله عليه وآله) wants to speak to you.' Then all creation will fall silent. 

The Prophet (صلى الله عليه وآله), will stand and say: 'O assembly of creation, whoever has done a favor, shown kindness, or done good to Me, let them now stand so that I may repay them.'

The people will respond: "By our fathers and mothers, what favor, kindness, or generosity do we have toward you? Indeed, the favor, kindness, and goodness are yours and Allah’s upon all creation." 

The Prophet will say to them: "Indeed, whoever sheltered anyone from my household, treated them kindly, clothed them when they were unclothed, or fed them when they were hungry, let them stand so I may repay them."

Then some people who have done these deeds will rise. A call will come from Allah (عز وجل) saying, "O Muhammad (صلى الله عليه وآله), O My Beloved, I have made entrusted their reward to You, so admit them into Paradise wherever you wish."

The Prophet (صلى الله عليه وآله) will then settle them in al-Waseela where they will not be veiled from Muhammad (صلى الله عليه وآله) and his AhlulBayt (عليهم السلام) Blessings of Allah be upon them all."

[Source: al-Faqih, Shaikh Saduq, Vol. 2, Pg. 65]