Is there any perspective that, we can say/call Shia Muslim or Sunni Muslim?

Question

Is there any perspective that, we can say/call Shia Muslim or Sunni Muslim? Is not it sin/bidah ?

Quran Verse

Indeed, those who have divided their religion and become sects - you, [O Muhammad], are not [associated] with them in anything. Their affair is only [left] to Allah; then He will inform them about what they used to do. Surah Al-An'am Verse 159

And hold firmly to the rope of Allah all together and do not become divided. And remember the favor of Allah upon you - when you were enemies and He brought your hearts together and you became, by His favor, brothers. And you were on the edge of a pit of the Fire, and He saved you from it. Thus does Allah make clear to you His verses that you may be guided. [Ali Imran : 103]( https://qurano.com/en/3-ali-imran/verse-103/

Say, [O believers], "We have believed in Allah and what has been revealed to us and what has been revealed to Abraham and Ishmael and Isaac and Jacob and the Descendants and what was given to Moses and Jesus and what was given to the prophets from their Lord. We make no distinction between any of them, and we are Muslims [in submission] to Him." Surah Al-Baqara Verse 136

Answer 1

To my opinion, you are right: We should be one, as God also is one, and we follow the Word of God that has come to us from the asme Prophet(s). You cited passages that sustain your thesis, so I need not cite to much.

The Shia is a very early separation of Islam and the first war between muslims. But God said:

Al Baquarah 2:190

Fight in the cause of God those who fight you, but do not commit aggression; God does not love the aggressors.

Theoretically, a true muslim must not wage war. Also through Jesus He said

Matthew 5:9

Blessed are the peacemakers, for they shall be called sons of God.

Christians are not supposed to wage war, either. But there have also been many wars between people who said they are Christians, and between Muslims and Christians.

Through the ages, some different views and traditions have developed in Shia and Sunni Islam but still the differences are rather small. We can accept most of the teachings from each other, and for the rest, we can tolerate each other accepting that there are some differences. By the way, there are very different approaches inside the branches between Salafist and Sufi in Sunni Islam, 12er Shia and Alewite in Shia.

But it would be better to say I practise Sunni / Shia or this type of Islam, as a practise and tradition rather than saying I am a Sunni / Shiite thinking like I a member of this or the other concurrent team.