"One who has completed and fulfilled these five faculties is an arahant. If they are weaker than that, one is practicing for the realization of the fruit of arahantship; if still weaker, one is a nonreturner; if still weaker, one is practicing for the path for the realization of the fruit of nonreturning; if still weaker, one is a once-returner; if still weaker, one is practicing for the realization of the fruit of once-returning; if still weaker, one is a stream-enterer; if still weaker, one is practicing for the realization of the fruit of stream-entry.
"But monks, I say that one in whom these faculties are completely and totally absent is' an outsider, one standing amid the worldlings"
(SN 48:18; V202), Translated by Bhikkhu Bodhi: In the Buddhas' Words, An Anthology of the Discourses from Pali Canon, 2005, Wisdom Publications, Inc., Page 385.
(Also read Indriya-vibhanga Sutta: Analysis of the Mental Faculties.)
The five spiritual faculties are faith (conviction), effort (vigor/energy), mindfulness, concentration and wisdom. Here we use a simile of a hand (see the figure above) and the strongest digit is the thumb and that it should be like the faith in the ptactice. The role of mindfulness in the center as the middle finger balancing the other four factors. It is important to have some amount of faith about the path to arrive at wisdom one day. Therefore the first goal of the Buddhist partitioner is to develop faith (on Buddha, Dhamma and the Sangha) through investigation of the path. There are two different forms of faith. Investigative faith (Akarawathi saddha) and blind faith/without proper beginning (Amulika saddha). In Buddhism we use the investigative faith (Akarawathi saddha).
There are two who are practicing for the realization of stream entry. They are the Faith follower and Dhamma follower. The faith follower has strong faith on the path and its results. He is the one who knows the arising and falling away of the five aggregates. The Dhamma follower has developed more wisdom than the faith follower. He sees the arising and passing away of the five aggregates. One who both knows and sees the arising and passing away of the five aggregates is a stream enterer. The stream enterer also has all the components of all the five faculties developed to some degree. The higher the degree of development of these faculties, the higher the stage of enlightenment. (see the above passage form the sutta). Buddha has discussed many advantages of being a stream enterer. Please read the links below (Click on the title).