Hadees Related to Kalima (Kalma)

Abu Hurairah Radiyallahu 'anhu narrates that Rasulullah Sallallahu 'alaihi wasallam said: He who says La ilaha illallah, it shall benefit him (be a means for his salvation) though before that he may be afflicted by what (Punishment) is to befall him.(Bazzar, Tabarani, Targhlb)

Hadees related to Kalima (Kalma)

Hudhaifah Radiyallahu 'anhu narrates that Rasulullah Sallallahu 'alaihi wasallam said: Islam will gradually fade as the design on cloth fades, until neither Siyam (fasting), nor Zakat (charity) nor Nusuk (religious devotion and sacrifice) will be known In a certain
night the Qur'an will be lifted from the hearts of men leaving not a single verse on the earth, and only a few groups of people wil remain, of old men and old women, saying: We found our forefathers reciting the Kalimah La ilaha illallah, so we are reciting it Silah
ibne-Zufr said to Hudhaifah Radiyallahu 'anhu: How will their saving of La ilaha illallah benefit them when they neither know Siyam, nor Zakat, nor Nusuk? Hudhaifah Radiyallahu 'anhu evaded him So he repeated his question thrice, each time Hudhaifah evaded him Then, after the third time, he turned and faced him saying:Silah! It will indeed save them from the Fire.(Mustadrak Hakim)

Hadees Related to Zainab (Razi Allahu Anhaa)

Munib Al Azdi Radiyallahu 'anhu narrates that during my days of ignorance before achieving (Islam), I saw Rasulullah Sallallahu 'alaihi wasallam, who said: O people! Say La ilaha illallah and be successful. Some of them spat on his face and someone threw dust
at him and some abused him till mid-day. Then a girl brought a bowl of water with which he washed his face and hands, and said: O my little daughter! Do not fear of your father's sudden murder, nor
disgrace. I enquired: Who is this girl? People said: She is Zainab, daugther of Rasulullah Sallallahu 'alaihi wasallam. She was a beautiful girl. (Tabarani, Majma-'uz-Zawaid)

Hadees related to Kalima (Kalma)

Ya'la ibne-Shaddad Radiyallahu 'anhu says that my father Shaddad Radiyallahu 'anhu  narrated to me in the presence of 'Ubadah ibne-Samit Radiyallahu 'anhuma who verified the narration. He said: We were present with Nabi Sallallahu 'alaihi wasallam. He inquired: Is there any stranger amongst you, that is, the people of the Book? We said: No, O Rasulallah! He then asked us to shut the door and said: Raise your hands and say La ilaha illallah. So, we raised our hands for a while (and recited the Kalimah). Afterwards Nabi Sallallahu 'alaihi wasallam lowered his hand and said: Alhamdulillah (Praise be to Allah). O Allah! Verily,You have sent me with this Kalimah and have ordered me to convey it and have promised me Paradise on it, and verily, You do not break Your Promise. He then said addressing the Sahabah: Indeed, rejoice for Allah has forgiven you! (Musnad
Ahmad, Tabarani, Bazzar, Majma-'uz-Zawaid)

Hadees related to Kalima (Kalma)

 Abu Hurairah Radiyallahu 'anhu narrates that Rasulullah Sallallahu 'alaihi wasallam said: Whenever a slave (of Allah) says La ilaha illallah sincerely, the doors of the skies are opened (for it to ascend) until it reaches the 'Arsh (Throne of Allah, and is readily
accepted) provided he abstains from major sins. (Tirmidhi)

Note: To say sincerely means that it is free from pretence and hypocrisy. Abstaining from major sins ensures its rapid acceptance, and even if it is recited without abstaining from the major sins, it is still beneficial and rewarding. (Mirqat-ul-Mafatih)