Dua is called 'prayer' in English. The word 'prayer' is not very clear. The English word 'prayer' is used for worship and also for dua. In Islam, the word used for worship is ibadat. The word dua is used to call out to God. In Islam, the concepts of dua and ibadat are different. Dua has a lot of importance.

According to a hadith: الدعاء مخ العبادة (Suna al-Tirmidhi 3371) Dua is the core of ibadat. Another hadith says: الدعاء هو العبادة (Sunan Abi Dawud 1479) Dua is ibadat. Why is this so? Ibadat is not the name of any form or ritual. Ibadat is a means of reaching out to God, or making contact with God. When you become connected to God, that is dua. This is why the Prophet said: Dua is ibadat

Yesterday a person called me to know about dua. He had many books of dua. He wanted to know which book of dua he should read. People think dua is repetition of certain memorized words, especially words in Arabic. Dua is not merely repetition of certain words. Dua is the restlessness of one's soul. When the restlessness of one's heart takes the form of words, that is dua. Dua is the name of a spirit, it isn't a form. Although dua consists of words, but those words represent one's inner feelings. These words don't have any meaning when the feelings are removed.