Purification is key to Salah
Sayyidina Ali (RA) narrated that the Prophet (SAW) said, "The key to purified. Its tahrim
(prohibition) is the takbir (saying Allahu Akbar to begin it) a (legality) is the taslim saying
assalaamu alaykum wa rahamatullah to end it."
[Ahmed1006, Abu Dawud 61,618 Ibn e Majah 275]