Hasan - narrated by at-Tirmidhee, lbn Khuzaymah and Ibn Hibbaan from Abu Sa'eed al-Khudree marfoo'aan and authenticated by al-Albaanee in (( Sahech ul-Jaami')) [351]
 

Rasoolullaah (s.a.w) said: If anyone guarantees me what is between his jaws and between his legs, I shall guarantee him Jannah

Saheeh - narrated by al-Bukhaaree from Sahl lbn Sa'd marfoo'aan
 

He (s.a.w) was asked as to what thing brings people into al-Jannah the most and he said: Taqwaa of Allaah and good character. Then he was asked as to what thing brings people into the Fire the most and he said : The mouth and the private-parts.

Hasan lsnaad - narratated by at-Tirmidhee [20041. Ibn Maajah [42461, Ahmad 12/29 1, 392, 4421, Ibin Hibbaan [ 1923 - al-Mawaarid], al- Baghawee In ((Shah us-Sunnah )) 113179-801 and others, and It was authenticated by al Albaanee in (( as-Saheehah )) [977] - from Abu Hurayrah marfoo'aan.
 

In a lengthy hadeeth, the Rasoolullaah (s.a.w) said:

Shall I not tell you about the peak of the matter, Its pillar and Its top-most part. I said: Yes 0 Rasoolullaah. He said: The peak of the matter Is Islaam,, the pillar Is salaah; and Its top-most part is Jihaad. Then he said: Shall I not tell you of the controlling of all that? I said: Yes 0 Rasoolullaah, and he took hold of his tongue and said: Restrain this. I said: 0 Nabee of Allaah, will what we say be held against us ? He said : May your mother be berieved of you, 0 Mu'aadh ! Is there anything which topples people on their faces - or he said : On their noses - Into Hell-Fire other than the harvests of their tongues

Saheeh - narrated by at-Tirmidhee 121 101, Ibn Maajah (39731 and Ahmad 15/23 11 from Mu'aadh - and the isnaad is hasan as al Albaanee says in ((al-'Irwaa')) [413]
 

O Rasoolullaah! Inform me of something which I may hold fast to ? He (s.a.w) said:

Say ! My Rabb Is Allaah and therafter be upright I said : 0 Rasoolullaah I What is the thing that you fear most for me ? He took hold of his tongue and said : This !

Saheeh - narrated by at- Tirmidhee 11965]. Ibn Maajah [39721 and Ahmad [3/4131 from Sufyaan ibn 'Abdullaah ath-Thaqafee
 

Rasoolullaah (s.a.w) said: Most of the sins of the Children of Aadam are from his tongue

Saheeh - narrated by at-Tabaraane 13/87/1-21, Abu'sh - Shaykh 12/101 and lbn 'Asaakir (11389/151 and authenticated in ((as-Saheeah)) [534]
 

Rasoolullaah (s.a.w) said: There Is not a part of the body except that It complains to Allaah because of the tongue - due to its haste / rashness

Saheeh - narrated by Abu Ya'laa (( Musnad )) [1/41. Ibn as-Sunnee [71. Ibn Abee'd-Dunyaa in ((al-Warr')) [Q.2/1651, Abu Nu'aym [209/1-2] and al-Bayhaqee in (( ash-Shub )) [2/65/91 see al-Albaanee's (( as-Saheehah )) [535]