Muwatta Malik #64

Yahya related to me from Malik from Nuaym ibn Abdullah al-Madani al-Mujmir that he heard Abu Hurayra say, "If someone does wudu and does it correctly and then goes off intending to do the prayer, then he is in prayer as long as he intends to do the prayer. A good action is written for every alternate step he makes and a wrong action is erased for the second. When you hear the iqama do not lengthen your stride, and the one who has the greatest reward is the one whose house is farthest away." They said, "Why, Abu Hurayra?" He replied, "Because of the greater number of steps."