Prayer is a communication to God. Many believe their prayers are answered and evidence of it is primarily reported in the Old and New Testament. Later miracles and graces have been reported by the Church and by common people. Prayer is done by those who trust the power of word and thought. Jesus taught people to say the Lord's Prayer.
Prayer can be spoken, silent (no talking), or in a song. It can be used to praise God or to ask for something including help and forgiveness. Prayers can be said over and over again as in a Rosary or just once. The Rosary includes Lord's Prayer and several others. Sister Lucia of Fatima said that Virgin Mary "in these last times in which we live has given new efficacy in the recitation of the Holy Rosary" and that " She has given this efficacy to such an extent that there is no problem, no matter how difficult it is, whether temporal or above all spiritual, in the personal life of each one of us, of our families … that cannot be solved by the Rosary". 
- "Rosarium Virginis Mariae on the Most Holy Rosary (October 16, 2002) - John Paul II". w2.vatican.va.
- John L. Esposito, ed. (2014). "Dua". The Oxford Dictionary of Islam. Oxford: Oxford University Press.
- Gardet, L. (2012). "Duʿāʾ". In P. Bearman; Th. Bianquis; C.E. Bosworth; E. van Donzel; W.P. Heinrichs (eds.). Encyclopaedia of Islam (2nd ed.). Brill. doi:10.1163/1573-3912_islam_COM_0195.
- Asani, A. S. (1987). "The khojahs of Indo‐Pakistan: The quest for an Islamic identity". Journal of Muslim Minority Affairs. 8: 31–41. doi:10.1080/02666958708716015.
- "The Importance of Dua in Islam". AZIslam.