Why Do We Raise Our Hands in the Opening Takbir?

Why do we raise our hands in the opening takbir?

It is sunnah to raise hands up while reciting the takbir al-iftitah. Because the Prophet Muhammad (saw) would raise his hands up while reciting this takbir (Nasa’i, Iftitah, 2; Tahawi, Sharhu ma‘ani’l-asar, I, 195-196). According to the Hanafi school, men raise their both hands by turning their palms to qiblah direction and aligning their thumbs with ear lobes. Women raise their hands up to their shoulders’ level (Marghinani, al-Hidayah, I, 307-309). Men also raise their hands up to their shoulders’ level according to other schools.

Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS