A conversation between Sāriputta, Anuruddha und Moggallāna in the Ketakivana in Sāketa, regarding the meaning of the word "sekha." A sekha is one who has only partially cultivated the four satipatthānas. S.v.174f.
Whoever cultivates psychic power, partially, can only do so by cultivating und developing the four bases of psychic power (iddhi-pādā). S.v.255.