Every good action or deed should be started with reciting Bismillah

Below are quoted some Authentic Traditions of the Prophet Muhammad (salAllahu alayhi wasalam) regarding Bismillah - In the name of Allah:

Saying Bismillah Is Recommended Before Eating:

The Prophet (salAllahu alayhi wasalam) said,

"Say Bismillah, eat with your right hand and eat what is in front of you."

[Bukhari 7/88, Muslim 2/207, Ahmad 17/92, Muwatta Malik 10/32 and Ibn Majah 1/557]

When Drinking Water:

Ibn Abbas (radiAllahu anhu) reported that the Messenger of Allah (salAllahu alayhi wasalam) said,

"Do not drink in one gulp like a camel, but in two or three [Gulps]. Mention the Name of Allah when you start drinking and praise Him after you have finished [Drinking].''

[Fath al-Bari 12/197 and Al-Trimidhi]

At The Beginning of Ablution:

The Prophet (salAllahu alayhi wasalam) said,

"Make Wudu [Ablution] in the name of Allah"

[An-Nasai 1/11 and Ibn Khuzaimah 1/84]

Before Having S-xual Intercourse with one's wife:

The Prophet (salAllahu alayhi wasalam) said,

"If anyone of you, when having sexual intercourse with his wife, says: In the name of Allah. O Allah! Protect us from Satan and also protect what you grant us [i.e. Coming offspring] from Satan and if it is destined that they should have a child, then Satan willnever be able to harm him." [Sahih Bukhari 7/94 and Sahih Muslim 2/1058]

When Entering The House:

Jabir (radiAllahu anhu) said: I heard the Messenger of Allah (salAllahu alayhi wasalam) saying,

"If a person mentions the Name of Allah upon entering his house or eating, Satan says, addressing his followers: `You will find no where to spend the night and no dinner.' But if he enters without mentioning the Name of Allah, Satan says [To his followers]; 'You have found [A place] to spend the night in, and if he does not mention the Name of Allah at the time of eating, Satan says: `You have found [A place] to spend the night in as well as food." [Sahih Muslim 2/206]

When Leaving The House:

The Messenger Of Allah (salAllahu alayhi wasalam) said,

"If anyone of you when leaving the house says In the name of Allah, I trust in Allah, there is no power and might except from Allah. Your needs shall be fulfilled, you shall be saved from difficulties and hardships. Shaitaan hearing these words leaves him."

[Al-Trimidhi 2/493]

When Slaughtering An Animal:

Anas (radiAllahu anhu) reported that Allah's Messenger (salAllahu alayhi wasalam) sacrificed two horned rams of white color with black markings over them. He also stated:

I saw him sacrificing them with his own hand and saw him placing his foot on their sides, and recited in the name of Allah and Glorified Him [Bismillah Allahu Akbar]

[Sahih al-Bukhari 7/133, Muslim 2/181, Abu Dawud 3/230, An-Nasai 7/231, Al-Trimidhi 5/76, Ibn Majah 2120]

When Fighting For The Cause Of Allah:

The Messenger of Allah (salAllahu alayhi wasalam) said,

"Fight in the name of Allah and in the way of Allah" [Sahih Muslim 2/69]

Recommended Because It Causes Humiliation To The Shaitan:

Abul Malih (radiAllahu anhu) said: I was riding on a mount behind the Prophet (salAllahu alayhi wasalam). It stumbled. Thereupon I said: May the devil perish! He said:

Do not say: May the devil perish! For if you say that, he will swell so much so that he will be like a house, and say: By my power. But say Bismillah for when you say that, he will diminish so much so that he will be like a fly.

[An-Nasai 6/142, Ahmad 5/59 and Abu Dawud 4946]

Recommended When Night Falls:

Allah's Apostle (salAllahu alayhi wasalam) said,

"When night falls stop your children from going out, for the devils spread out at that time. But when an hour of the night has passed, release them and close the doors and mention Allah's Name, for Satan does not open a closed door. Tie the mouth of your water-skin and mention Allah's Name; cover your containers and utensils and mention Allah's Name. Cover them even by placing something across it, and extinguish your lamps. "

[Sahih al-Bukhari 7/527 and Abu Dawud 3722]

When Placing The Body Of The Deceased In The Grave:

The Prophet of Allah (salAllahu alayhi wasalam) said,

"When you are lowering the deceased in the grave you should say In the name of Allah and in accordance to the Sunnah of the Messenger of Allah." [Ahmad 8/58 and Al-Hakim 1/366]

The Virtues Of Saying Bismillah:

Uthman bin Abu al-As Al-Thaqafi (radiAllahu anhu) reported that he made a complaint of pain to Allah's Messenger (salAllahu alayhi wasalam) that he felt in his body at the time he had become Muslim. Thereupon Allah's Messenger (salAllahu alayhi wasalam) said:

Place your hand at the place where you feel pain in your body and say in the name of Allah three times and seven times I seek refuge with Allah and with His Power from the evil that I find and that I fear. [Muslim 2/280]

When Writing A Letter Bismillah Should Also Be Written:

Abu Sufyan (radiAllahu anhu) said that the contents of the letter were as follows:

"In the name of Allah the Most Gracious, the Most Merciful, [This letter is] from Muhammad the slave of Allah and His Apostle to Heraclius the ruler of Byzantine. Peace be upon him, who follows the right path. Furthermore I invite you to Islam, and if you become a Muslim you will be safe, and Allah will double your reward, and if you reject this invitation of Islam you will be committing a sin by misguiding your peasants." [Bukhari 4/191, Muslim 2/91, Al-Trimidhi 7/500] [Queen Sheba] said O chief! Surely an honorable letter has been delivered to me Surely it is from Sulaiman, and surely it is in the name of Allah, the Most Gracious, the Most Merciful; [Al-Quran, Surah Al-Naml, Ayahs 29-30]