Doing everything for the sake of Allah

 Doing everything for the sake of Allah. 

One of the act of worship we do not adhere is to make an act of worship for the sake of Allah. 

Allah says in Quran, 

 Al-Bayyinah 98:5

And they were not commanded except to worship Allāh, [being] sincere to Him in religion, inclining to truth, and to establish prayer and to give zakāh. And that is the correct religion.

Allah says, 

Az-Zumar 39:11

قُلْ إِنِّىٓ أُمِرْتُ أَنْ أَعْبُدَ ٱللَّهَ مُخْلِصًا لَّهُ ٱلدِّينَ 

Say, [O Muḥammad], "Indeed, I have been commanded to worship Allāh, [being] sincere to Him in religion.

Ikhlas is the sweetness of the deed and any action one does without it is null.

As in the hadith,

Narrated Jundub:

The Prophet (ﷺ) said, "He who lets the people hear of his good deeds intentionally, to win their praise, Allah will let the people know his real intention (on the Day ofResurrection), and he who does good things in public to show off and win the praise of the people, Allah will disclose his real intention (and humiliate him).