Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with this chain (it is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him) that the Messenger of Allah, peace and blessings be upon him, said: "Shall I not tell you of an action by which Allah erases sins and raises ranks? Performing ablution thoroughly in times of difficulty, taking many steps towards the mosques, and waiting for the next prayer after the prayer—this is «رباط» (preparation for jihad), this is «رباط», this is «رباط»."