Paṭhamarahogatasutta

sn52.1:2.1 Then Venerable Mahāmoggallāna knew what Venerable Anuruddha was thinking. As easily as a strong person would extend or contract their arm, he reappeared in front of Anuruddha,

sn52.1:2.2 and said to him:

sn52.1:2.3 “Reverend Anuruddha, how do you define the undertaking of the four kinds of mindfulness meditation by a mendicant?”