1. Caṅkama Sutta.– On one occasion at Rājagaha, Venerable Sāriputta, Mahā-Moggallāna, Mahākassapa, Anuruddha, Puṇṇa Mantāṇiputta, Upāli, Ānanda, and Devadatta were walking back and forth not far from the Blessed One each with a large number of bhikkhus.
The Buddha addressed the monks saying that all those monks walking with Venerable Sāriputta were of great wisdom, all those walking with Mahā-Moggallāna were of great psychic power, all those walking with Mahā-Kassapa were proponents of the ascetic practices, all those walking with Anuruddha possessed the divine-eye, all those walking with Puṇṇa Mantāṇiputta were speakers on Dhamma, all those walking with Upāli were experts on the Vinaya, all those walking with Ānanda were very learned, and all those walking with Devadatta were of evil wishes.
That was the nature of beings to group together on the basis of their dispositions. S.ii.155. See also Ahirikamūlaka Sutta, etc.
2. Caṅkama Sutta.– The five advantages of a walking path (caṅkama): it trains one to travel, encourages striving, it is healthy, it improves digestion and promotes concentration. A.iii.29.