You'll have to take that up with the Buddha and his concept of the "four pairs" then...
AN 5.179 wrote:he is endowed with verified confidence in the Sangha: 'The Sangha of the Blessed One's disciples who have practiced well... who have practiced straight-forwardly... who have practiced methodically... who have practiced masterfully — in other words, the four pairs, the eight individuals — they are the Sangha of the Blessed One's disciples: worthy of gifts, worthy of hospitality, worthy of offerings, worthy of respect, the incomparable field of merit for the world.' This is the third pleasant mental abiding in the here & now that he has attained, for the purification of the mind that is impure, for the cleansing of the mind that is unclean.
Metta,Translator note wrote:The four pairs are (1) the person on the path to stream-entry, the person experiencing the fruit of stream-entry; (2) the person on the path to once-returning, the person experiencing the fruit of once-returning; (3) the person on the path to non-returning, the person experiencing the fruit of non-returning; (4) the person on the path to arahantship, the person experiencing the fruit of arahantship. The eight individuals are the eight types forming these four pairs.
Paul.