Allah, all praises and glory be to Him, has said:
“Verily, your Lord has said: ‘Call upon Me, and I will answer you!’ Those who are (too) arrogant to worship Allah will enter Hell, humiliated!” (Surah Ghafir:60)
In this verse, Allah has commanded us to ask Him and petition Him, and has stated that those who do not do this are among those too arrogant to worship Him. From this, we can clearly understand that du’a is from among the acts of worship. This was also explicitly stated by the Prophet, peace and blessings of Allah be upon him, who said:
“Du’a is worship.” (Recorded in Ahmad)
Du’a is also equated with the Deen or the entire religion by Allah, all praises and glory be to Him, when He says:
“He is the Hayy (Ever-Living), there is no deity except Him. So make du’a to Him, to Him is the Deen.” (Surak Ghafir:65)
There is no other act of ibadah or worship that has been given this honour.
One of the benefits of understanding that du’a is a form of worship is that we realise its manner and etiquettes must be taken from the Qur’an and Sunnah.
Just as we cannot use our own whims and desires to decide how we pray and fast, so too we cannot use our own whims and desires when it comes to deciding the best manner in which to perform du’a.