The Messenger of Allah ﷺ said, "Shall I not tell you of that by which Allah erases sins and raises ranks? Performing wudu thoroughly despite difficulties, taking many steps to the mosques, and waiting for the next prayer after the prayer. That is the true ribat, that is the true ribat, that is the true ribat."
أخبرنا قتيبة عن مالك عن العلاء بن عبد الرحمن عن أبيه
أن رسول الله ﷺ قال ألا أخبركم بما يمحو الله به الخطايا ويرفع به الدرجات إسباغ الوضوء على المكاره وكثرة الخطا إلى المساجد وانتظار الصلاة بعد الصلاة فذلكم الرباط فذلكم الرباط فذلكم الرباط
Reported by Muslim, Book of Purification, Chapter on the merit of performing wudu thoroughly despite hardship, no. 251, from the hadith of Malik through this same chain. It also appears in the Muwatta (Yahya's version) 1/161, and in Kubra, no. 139.