‘Abdullāh ibn ‘Amr ibn al-‘Ās (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Returning from battle is like going to battle (in reward)."
This Hadīth highlights the grace and favor of Allah, the Almighty, upon His servants when they perform acts of worship. Just as they are rewarded for going out to do acts of worship, they are also rewarded when they return home after having performed them. Therefore, the Prophet (may Allah's peace and blessings be upon him) said that the one who returns from a battle is like the one who is going out to a battle; they both receive the same reward. This is similar to the case of the person walking to the mosque; he receives reward for walking to the mosque and reward for returning home from it.