An Nasai: Hadith 1408

The Messenger of Allah (ﷺ) said: "Whoever washes (ghassala) and performs ghusl, and comes early to the masjid and sits near the imam, is attentive and does not engage in idle talk, for every step he takes he will have (the reward of) a year's worth of good deeds, its fasting and Qiyam prayer."