The Buddha describes the four kinds of monks

The Sutta-Nipata

5. CUNDA SUTTA

Cunda the Smith

The Buddha describes the four kinds of monks
1 Cunda: I ask the sage Buddha of great wisdom, Lord of Dhamma, who is free from craving, the noblest of guides; how many kinds of monks are there in the world? Please tell me.

2 The Buddha: Cunda, there are four kinds of monks, not a fifth. I shall elucidate them to you, since you ask me: (i) one kind has won the Path, (ii) one expounds the Path, (iii) one lives on the Path, and (iv) one defiles the Path.
3 Cunda: Whom does the Buddha describe as one who has won the Path?

4 The Buddha: One who overcomes uncertainty, is freed from sorrow, delights in Nibbana, is detached, a guide of men and gods - such a person is said by the Buddha to be one who has won the Path.

5 Here, one knows Nibbana as the noblest (state) and expounds and explains the Dhamma; that sage who destroys uncertainly, is desireless - this second monk is called the one who expounds the Path.

6 One who has controlled himself mindfully, lives well on the Path according to the words of Dhamma well expounded; one who practices correct principles - this third of monk is called the one who lives on the Path.
7 One who disguises himself by wearing the robes of the well-conducted ones, travels for gain, disgraces families, is impudent, deceitful, unrestrained, a gossip and waffler pretending to be a real monk - he is one who defiles the Path.
8 Having comprehended these (four) he who is well-versed, house-holder, who is a noble, wise disciple and who has understood that ‘all of them are not alike’; seeing thus, he does not diminish his confidence. How could the defiled one and the undefiled one, the pure and the impure one, be considered as equals?