The Messenger of Allah said:
"Al-Hasan and al-Husain are the chiefs of the youth of Paradise and Fatimah is the chief of their women."

References:

(1) Sahih al-Tirmidhi, v5, p660, on the authority of Abu Sa'id and Hudhayfa

(2) Sunan Ibn Majah, Introduction 8

(3) al-Tabarani, on the authorities of: Umar, Ali, Jabir, Abu Hurayrah, Usamah Ibn Zaid, al-Baraa, Ibn 'Adi, and Ibn Masud.

(4) al-Kubra, by al-Nisa'i

(5) Musnad Ahmad Ibn Hanbal, v1, pp 62,82, v3, pp 3,64, v5, p391

(6) Fada'il al-Sahaba, by Ahmad Hanbal, v2, p771, Tradition #1360

(7) al-Mustadrak, by al-Hakim, v3, pp 166,167

(8) Hilyatul Awliyaa, by Abu Nu'aym, v5, p71

(9) Majma' al-Zawa'id, by al-Haythami, v9, p187

(10) Tuhfatul Ashraf, by Lumzi, v3, p31

(11) Ibn Habban, as mentioned in al-Mawarid, pp 551,553

(12) al-Sawa'iq al-Muhriqah, by Ibn Hajar Haythami, Ch. 11, section 3, p290

(13) Mishkat al-Masabih, by Khatib al-Tabrizi, English Version, Tdadition #6154

The Messenger of Allah said:

"Husain is from me and I am from Husain."

References:

(1) Musnad Ahmad Ibn Hanbal, v4, p172

(2) Fadha'il al-Sahaba, by Ahmad Hanbal, v2, p772, Tradition #1361

(3) al-Mustadrak, by al-Hakim, v3, p 177

(4) Amali, by Abu Nu'aym al-Isbahani, p 64

(5) al-Kuna wal Asmaa, by al-Dulabi, v1, p88

(6) al-Tabarani, v3, p21

(7) Adab by al-Bukhari, also al-Tirmidhi and Ibn Majah, as quoted in:

(8) al-Sawa'iq al-Muhriqah, by Ibn Hajar Haythami, Ch. 11, section 3, p291

(9) Mishkat al-Masabih, by Khatib al-Tabrizi, English Version, Tdadition #6160

The Prophet (PBUH) looked toward Ali, Hasan, Husain, and Fatimah (AS), and then said:

"I am in war with those who will fight you, and in peace with those who are peaceful to you."

References:

(1) Sahih al-Tirmidhi, v5, p699

(2) Sunan Ibn Majah, v1, p52

(3) Fadha'il al-Sahaba, by Ahmad Ibn Hanbal, v2, p767, Tradition #1350

(4) al-Mustadrak, by al-Hakim, v3, p149

(5) Majma' al-Zawa'id, by al-Haythami, v9, p169

(6) al-Kabir, by al-Tabarani, v3, p30, also in al-Awsat

(7) Jami' al-Saghir, by al-Ibani, v2, p17

(8) Tarikh, by al-Khateeb al-Baghdadi, v7, p137

(9) Sawaiq al-Muhriqah, by Ibn Hajar al-Haythami, p144

(10) Talkhis, by al-Dhahabi, v3, p149

(11) Dhakha'ir al-Uqba, by al-Muhib al-Tabari, p25

(12) Mishkat al-Masabih, by Khatib al-Tabrizi, English Version, Tdadition #6145

The Messenger of Allah said:

"He who loves al-Hasan and al-Husain, loved me, and he who makes them angry has made me angry."

Reference:

- Sunan Ibn Majah,

- al-Mustadrak, by al-Hakim, from Abu Hurairah

- Musnad Ahmad Ibn Hanbal, as quited in:

- al-Sawa'iq al-Muhriqah, by Ibn Hajar Haythami, Ch. 11, section 3, p292

It has been narrated that  The Messenger of Allah said:

"I named Hasan and Husain and Muhsin the names of the sons of Aaron (Haroon) who were: Shubbar, Shubair, and Mushbir."

References:

(1) Sunan Abu Dawud al-Tilyasi, v1, p232 (without mentioning Muhsin)

(2) Fadha'il al-Sahaba, by Ahmad Ibn Hanbal, v2, p774, Tradition #1365

(3) al-Mustadrak, by al-Hakim, v3, pp 165,168

(4) Kashf al-Astar, by al-Bazzar, v2, p416

(5) Ibn Habban, as quoted in al-Mawarid, p551

(6) al-Tabarani, v3, p100

(7) Idhaah, Abdul Ghani, from Salman al-Farsi

(8) al-Mu'jam, by al-Baghawi, as quoted in:

(9) al-Sawa'iq al-Muhriqah, by Ibn Hajar Haythami, Ch. 11, section 3, p292

Usamah ibn Zayd narrated:

     I went to the Prophet (PBUH&HF) one night about something I required and he came out with something (I did not know what) under his cloak.When I had finished telling him my business I asked him what he had   under his cloak, and when he opened it I saw al-Hasan and al-Husayn on his hips. He then said,

"These are my sons and my daughter's sons. O Allah, I love them, so I beseech Thee to love them and those who love them."                       

References:

• Sahih Tirmidhi, per:

• Mishkat al-Masabih, by Khatib al-Tabrizi, English Version, Tdadition #6156

Anas ibn Malik Narrated:

When Allah's Messenger (PBUH&HF) was asked which member of his family was dearest to him, he replied,

"Al-Hasan and al-Husain." He used to say to Fatimah, "Call my two sons to me," and then would sniff and    cuddle them.

References:

- Sahih Tirmidhi, per:

- Mishkat al-Masabih, by Khatib al-Tabrizi, English Version, Tdadition #6158

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