First: Comparing the intention with the Takbir (opening of the prayer) in reality or in ruling: The real comparison is the comparison of the intention for the Takbir without any interruption between them by an external action that prevents connection, such as eating, drinking, speaking, and the like. However, walking to prayer and performing ablution do not prevent the connection between the intention and the Takbir. The ruling comparison is to present the intention before starting the prayer without engaging in an external action that prevents the connection between the intention and the Takbir, such as eating, drinking, speaking, and the like. For example, if someone intends to pray Dhuhr during ablution and does not engage in any external action after the intention, then he reaches the place of prayer and the intention has not occurred to him, his prayer is valid based on the previous intention. Second: He must know in his heart which prayer he is praying, such that if he is asked: "Which prayer are you praying?" he answers immediately without effort; his prayer is valid. It is not required to verbalize the intention, but it is recommended; because it helps to bring the intention to mind, due to the differences in time and the many distractions on hearts after the time of the successors. Third: Specifying the intention in obligatory and mandatory prayers: such as making up a voluntary prayer that was invalidated, a vow, Witr, the two Rak'ahs of Tawaf, and the two Eid prayers; due to the differences in the reasons for the prayer, specification is necessary. It is not required to specify the intention in voluntary prayers. See: Hidayah Ibn Al-Imad p. 456, Al-Durr Al-Mukhtar 1: 415, Naf' Al-Mufti p. 237, Al-Maraqy p. 217, and Hashiyat Al-Tahawi p. 217.