Majma al-Zawaid 772 — One who initiates a good practice or otherwise

Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever initiates a good practice receives its reward as long as it is acted upon, in his lifetime and after his death, until it is abandoned; and whoever initiates an evil practice, its sin remains upon him as long as it is not abandoned. Whoever dies while guarding the frontier in the way of Allah, the deed of the frontier guard continues for him until he is raised again on the Day of Resurrection."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators have been declared trustworthy.