The Prophet ﷺ said, "Shall I guide you to what Allah uses to erase sins and raise ranks?"They replied, "Of course, Messenger of Allah."He said, "Performing wudu thoroughly despite hardships, taking many steps to the mosques, and waiting for the next prayer after the previous one. That is the true ribat."
عن النبي ﷺ: ألا أدلكم على ما يمحو الله به الخطايا، ويرفع به الدرجات؟ قالوا: بلى، يا رسول الله. قال: إسباغ الوضوء على المكاره، وكثرة الخطى إلى المساجد، وانتظار الصلاة بعد الصلاة، فذلكم الرباط.
Muslim narrated it in the Book of Purification (251), through several routes, from Ismail bin Jafar, who said, Ala bin Abdul-Rahman told me, from his father, from Abu Hurairah, and he mentioned it. There are other hadiths with the same meaning in the Book of Purification.The second meaning is the stationing of fighters at the front lines facing the enemy, and guarding the frontiers of Islam against the entry of the enemies of Allah into the lands of the Muslims.