The importance of tawheed.

 The importance of tawheed. 

Alhamdulillah, Tawheed came from the word ahad or waheed meaning one. 

Allah s.w.t mentioned in the Quran 

Say, Allah is one and only. 

Surah112;1.

Believing in Allah as one and only. 

Allah says in Quran, 

An-Nahl 16:36

And We certainly sent into every nation a messenger, [saying], "Worship Allāh and avoid ṭāghūt."[1] And among them were those whom Allāh guided, and among them were those upon whom error was [deservedly] decreed. So proceed [i.e., travel] through the earth and observe how was the end of the deniers.

Without tawheed, there is no islam. 

The messengers all came to call people to worship Allah and seek protection from him, ask for his guidance. 

If one associates partner with Allah and dies, his deeds are all nullified 

Allah says, 

Az-Zumar 39:65

And it was already revealed to you and to those before you that if you should associate [anything] with Allāh, your work would surely become worthless, and you would surely be among the losers.

If we die with shirk, our solaah, Hajj, and good deeds are rejected. 

Allah says, 

Al-Ma'idah 5:72

They have certainly disbelieved who say, "Allāh is the Messiah, the son of Mary" while the Messiah has said, "O Children of Israel, worship Allāh, my Lord and your Lord." Indeed, he who associates others with Allāh - Allāh has forbidden him Paradise, and his refuge is the Fire. And there are not for the wrongdoers any helpers.

Anyone who dies with shirk, such a person paradise is forbidden for him.