Hadith 1:

حدثنا أبو علي محمد بن أحمد بن محمد بن يحيى المعاذي النيسابوري قال: حدثنا أبو الحسن علي بن أحمد بن علي البصري المعدل قال: رأى رجل من الصالحين فيما يرى النائم رسول الله (ص) فقال: يا رسول الله من أزور من اولادك؟ فقال: إن من أولادي من اتاني مسموما وإن من أولادي من أتاني مقتولا، قال: فقلت له فمن أزور منهم يا رسول الله مع تشتت مشاهدهم أو قال أماكنهم؟ قال: من هو أقرب منك يعني بالمجاورة وهو مدفون بأرض الغربة قال: فقلت يا رسول الله تعني الرضا عليه السلام؟ فقال (ص): قل: صلى الله عليه قل صلى الله عليه ثلاثا

A good person (صالح) saw the Prophet (ص) in his dream. He asked the Prophet (ص) , "O Prophet (ص) Which one from your offspring should I go to visit?"

The Prophet (ص) said، "A few of my descendants who have come to me have been poisoned & a few of my offspring who have come to me have been killed"

Then he asked the Prophet (ص),  "O Prophet! Given the great distances between their shrines (or locations), which one of them shall I visit?"

The Prophet (ص) said, "Visit the one who is closest to you - that is whom you are near to and is buried in the land of loneliness."

Then he asked the Prophet (ص), "O Prophet (ص)! Do you mean Ar-Ridha (ع)"?

The Prophet (ص) said, "Say: Allah's Blessings be upon him. Say: Allah's Blessings be upon him. Say: Allah's Blessings be upon him ... three times"

[Note: The last statement of the Prophet indicates that we should say "Blessings be upon him" when taking the name of the Imam's (ع)

[Source: Uyoon al-Akhbar al-Redha, Chapter. 69, Hadith. 5]

Hadith 2:

عن أبي عبد الله الصادق (ع): يقتل حفدتي بأرض خراسان في مدينة يقال لها طوس، من زاره إليها عارفا بحقه أخذته بيدي يوم القيامة وأدخلته الجنة وإن كان من أهل الكبائر، قلت: جعلت فداك, وما عرفان حقه؟ قال: يعلم أنه مفترض الطاعة غريب شهيد، من زاره عارفا بحقه أعطاه الله عز وجل أجر سبعين شهيدا ممن استشهد بين يدي رسول الله (ص) على حقيقة.

Narrated that Imam Sadiq (ع) said,

"My grandson will be killed on the land of Khurasan in the city called Toos. Whoever visits Him (goes for Ziyarat) there recognizing His rights, I will take him by his hand on the day of Judgement and make him enter heaven even if he has committed greater sins."

The narrator said, "May I be sacrificed for You, what is the recognition of His rights?"

Imams (ع) replied, "Knowing that His obedience is obligatory and that He is away from His hometown (Ghareeb) and a Martyr (shaheed). Whoever goes for His Ziyarat recognizing His rights, Allah (عز و جل) will give him rewards of 70 martyrs who were killed right in front of Allahs Prophet (ص) ."

[Source: al-Amali, Shaikh Sadooq, Pg. 183]

Hadith 3:

حَدَّثَنا عَلِيٍّ بن أَحمَد بن مُحَمَّد بن عمران الدَّقاق ومُحَمَّدبن أَحمَد السناني وعَلِيٍّ بن عَبدُ اللَّه الوَرَّاقِ والحُسَين بن إِبراهِيم بن هِشام المكتب رضي الله عنهم قالوا حَدَّثَنا مُحَمَّد بن أبي عَبدُ اللَّه الكوفي الأسدي عَن أَحمَد بن مُحَمَّد بن صالح الرازي عَن حمدان الديواني قالَ قالَ الرِّضا عَلَيْهِ السَّلامُ مَنْ زَارَنِي عَلَى بُعْدِ دَارِي أَتَيْتُهُ يَوْمَ الْقِيَامَةِ فِي ثَلاثَةِ مَوَاطِنَ حَتَّى أُخَلِّصَهُ مِنْ أَهْوَالِهَا إِذَا تَطَايَرَتِ الْكُتُبُ يَمِيناً وَشِمَالاً وَعِنْدَ الصِّرَاطِ وَعِنْدَ الْمِيزَانِ

Narrated that Imam al-Ridha (ع) said,

“Whoever visits me despite the far distance to my tomb, I will come to him on the day of Judgement on three occasions until I liberate him from its terrors: 

1- When the Letters of Deeds are handed to either the right hand or left hand,

2- At the moment of crossing the bridge over Hell (Serat), and 

3- At the time when the Scale of Deeds (i.e. Mizaan, measuring the amount of good vs. bad deeds) is set up.”

[Source: Uyun akhbar al-Ridha, Shaikh Sadooq, Vol. 2, Ch, 36, Hadith. 2]

Hadith 4:

عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنْ عَلِيِّ بْنِ مَهْزِيَارَ قَالَ: قُلْتُ لِأَبِي جَعْفَرٍ ع جُعِلْتُ فِدَاكَ زِيَارَةُ الرِّضَا ع أَفْضَلُ أَمْ زِيَارَةُ أَبِي عَبْدِ اللَّهِ الْحُسَيْنِ ع فَقَالَ زِيَارَةُ أَبِي أَفْضَلُ وَ ذَلِكَ أَنَّ أَبَا عَبْدِ اللَّهِ ع يَزُورُهُ كُلُّ النَّاسِ وَ أَبِي لَا يَزُورُهُ إِلَّا الْخَوَاصُّ مِنَ الشِّيعَةِ

Narrated that Ali bin Mahziyar said, I asked Abu Jafar Imam Taqi (ع), 

"May I be sacrificed for You, Is the Ziyarat of al-Ridha (ع) superior (Afdhal) or the Ziyarat of Abu Abdullah al-Husain (ع)?"

Imam (ع) replied, "The pilgrimage to my father (al-Ridha ع) is superior, because all the people go to Ziyarat of Aba Abdullah al-Husain (ع), while none go to the Ziyarat of My Father al-Ridha (ع) except the special ones of the Shiites."

[Source: al-Kafi, Vol. 4, Pg. 584] 

Hadith 5:

عَن أبي الحَسَن عَلِيٍّ بن مُوسَى الرِّضا عَلَيْهِ السَّلامُ أنه قالَ: إِنَّ بِخُرَاسَانَ لَبُقْعَةً يَأْتِي عَلَيْهَا زَمَانٌ تَصِيرُ مُخْتَلَفَ الْمَلائِكَةِ فَقَالَ فَلا يَزَالُ فَوْجٌ يَنْزِلُ مِنَ السَّمَاءِ وَفَوْجٌ يَصْعَدُ إِلَى أَنْ يُنْفَخَ فِي الصُّورِ.فَقِيلَ لَهُ يَا ابْنَ رَسُولِ اللَّهِ وَأَيَّةُ بُقْعَةٍ هَذِهِ قَالَ هِيَ بِأَرْضِ طُوسَ فَهِيَ وَاللَّهِ رَوْضَةٌ مِنْ رِيَاضِ الْجَنَّةِ مَنْ زَارَنِي فِي تِلْكَ الْبُقْعَةِ كَانَ كَمَنْ زَارَ رَسُولَ اللَّهِ‏ صَلَّى اللهُ عَلَيْهِ وَآلِهِ وَكَتَبَ اللَّهُ تَبَارَكَ وَتَعَالَى لَهُ ثَوَابَ أَلْفِ حَجَّةٍ مَبْرُورَةٍ وَأَلْفِ عُمْرَةٍ مَقْبُولَةٍ وَكُنْتُ أَنَا وَآبَائِي شُفَعَاءَهُ يَوْمَ الْقِيَامَةِ

Narrated that Imam Ridha (ع) said,

"Indeed there is a place/site in Khurasan which at a point in time will become a place of coming and going of angels. A group of angels will be descending from the sky, and another group will be ascending until the Trumpet is blown"

The Imam (ع) was asked, "O Son of the Prophet of Allah (ع), which place is that?"

Imam (ع) said, "It is in the land of Toos. And, by Allah, it is a Garden from amongst the Gardens of Heaven. Whoever visits Me there in that place, it is as if he has visited Prophet of Allah (ص). And Allah (تبارك و تعالى) will record for him the reward of one thousand accepted Hajj, and one thousand accepted Umra. And I and my forefathers will be his intersessors on the day of Judgement."

[Source: Uyoon al-Akhbar al-Ridha, Vol. 1, Pg. 286]

Hadith 6:

حَدَّثَنا أَحمَد بن زياد بن جَعفَر الهمداني‏ رَضِىَ اللهُ عَنْهُقالَ حَدَّثَنا عَلِيٍّ بن إِبراهِيم بن هاشِمٍ عَن أبِيهِ عَن ياسر الخادم قالَ قالَ عَلِيٍّ بن مُوسَى الرِّضا عَلَيْهِ السَّلامُ لا تُشَدُّ الرِّحَالُ إِلَى شَيْ‏ءٍ مِنَ الْقُبُورِ إِلاّ إِلَى قُبُورِنَا أَلا وَإِنِّي مَقْتُولٌ بِالسَّمِّ ظُلْماً وَمَدْفُونٌ فِي مَوْضِعِ غُرْبَةٍ فَمَنْ شَدَّ رَحْلَهُ إِلَى زِيَارَتِي اسْتُجِيبَ دُعَاؤُهُ وَغُفِرَ لَهُ ذُنُوبُهُ.

Narrated through a chain of trustworthy/reliable narrators that Ali ibn Musa al-Rida (عليه السلام) said, 

"You should not be determined to travel to any graves other than Our graves. Verily, I will be unjustly killed with poison and buried in a strange place, so whoever strides to come to visit Me (Ziyarat), his supplication with be answered and his sins will be forgiven."

[Source: Uyoon Akhbar al-Rida, Vol. 1, Pg. 285]

Hadith 7:

From a Ziyarat of Imam Ali ibn Musa al-Rida (عليه السلام) as narrated from Imam Muhammad ibn Ali al-Jawwad (عليه السلام):

السَّلَامُ عَلَى مَنْ أَسْمَاؤُهُمْ وَسِيلَةُ السَّائِلِينَ وَ هَيَاكِلُهُمْ أَمَانُ الْمَخْلُوقِينَ وَ حُجَجُهُمْ إِبْطَالُ شُبَهِ الْمُلْحِدِينَ

"Salutations be upon those whose names are the means of intercession for those who ask, whose existence is the safety of the creations, and whose arguments/proofs is the invalidation of the doubts of the disbelievers."

السَّلَامُ عَلَى مُفْتَخَرِ الْأَبْرَارِ وَ نَائِي الْمَزَارِ وَ شَرْطِ دُخُولِ الْجَنَّةِ أَوِ النَّارِ

"Peace be upon the pride of the righteous, and the one whose shrine is at a distant place, and the one who is a condition for entering Paradise or Hell."

[Source: Bihar al-Anwar, Vol. 99, Pg. 53-54]

Hadith 8:

Imam Sadiq (عليه السلام) said the following about Imam Kazim (عليه السلام) in a lengthy narration:

وَقَدْ عُلِّمَ الْحُكْمَ وَالْفَهْمَ وَالسَّخَاءَ وَالْمَعْرِفَةَ بِمَا يَحْتَاجُ إِلَيْهِ النَّاسُ وَمَا اخْتَلَفُوا فِيهِ مِنْ أَمْرِ دِينِهِمْ وَدُنْيَاهُمْ وَفِيهِ حُسْنُ الْخُلُقِ وَحُسْنُ الْجَوَابِ وَهُوَ بَابٌ مِنْ أَبْوَابِ الله عَزَّ وَجَلَّ وَفِيهِ أُخْرَى خَيْرٌ مِنْ هَذَا كُلِّهِ فَقَالَ لَهُ أَبِي وَمَا هِيَ بِأَبِي أَنْتَ وَأُمِّي قَالَ (عَلَيْهِ السَّلام) يُخْرِجُ الله عَزَّ وَجَلَّ مِنْهُ غَوْثَ هَذِهِ الامَّةِ وَغِيَاثَهَا وَعَلَمَهَا وَنُورَهَا وَفَضْلَهَا وَحِكْمَتَهَا

"He (i.e. Imam Kazim عليه السلام) has been given the knowledge of the laws, the understanding, the generosity and the recognition of all that people need, and of all things about which the people differ in matters of their religion or their world. And in him there are good moral qualities and good answers, and He is a gate from the gates of Allah (عز وجل).

And in him (i.e. Imam Kazim عليه السلام) there is another quality that is better than all of these. 

The Narrator asked, “What that quality is, may my father and mother be sacrificed for You?"

The Imam (عليه السلام) said, "Allah (عز وجل), will bring about from him the help/relief (غوث) of this Ummah and the helper (غياث) of the Ummah, the knowledge, the light, the excellence, and the wisdom of this Ummah. (i.e. referring to Imam Ridha عليه السلام)."

[Source: al-Kafi, Vol. 1, Kitab al-Hujjah, Ch. 72, Hadith. 14]