Sunan Ibn Majah
427
Hasan Sahih+2

It was narrated from Abu Sa'eed Khudri that he heard :The Messenger of Allah say: "Shall I not tell you of something by means of which Allah expiates for sins and increases good deeds?" They said: "Yes, O Messenger of Allah." He said: "Perform ablution properly despite difficulties, increasing the number of steps one takes towards the mosque and waiting for the next prayer after prayer

Hasan SahihAl-Albani
Hasan SahihMuhammad Fouad Abd al-Baqi