Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Prayer in a dream is praiseworthy in all cases. It indicates payment of debt, fulfillment of trusts, adherence to covenants, and salvation from worries. The obligatory prayer (Fardh) indicates fulfilling trusts and avoiding prohibitions. Whoever sees himself praying in a direction other than the Qibla is committing a great sin or straying from the truth.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Prayer in a dream indicates a position of authority, a high rank, or the fulfillment of a need. Whoever sees himself leading people in prayer (Imam) will gain authority and high status. Whoever abandons prayer in a dream out of disdain is disrespecting his religion and its laws. Sending blessings on the Prophet (PBUH) indicates strength in religion and victory over enemies.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Prayer is interpreted as prestige and status with God and people. Whoever sees himself performing a complete prayer, Allah has accepted his deed and fulfilled his need. Praying in an impure place indicates corruption in religion and falling into immoral acts. The prayer for rain (Istisqa) indicates fear of the ruler or high prices.