Sotah, Chapter Nine, Mishnah Ten
There are four practices mentioned as being discontinued in this mishnah.
1) Yohanan the high priest brought to an end the confession made at the presentation of the tithe.
2) He also discontinued the wakers and the knockers
3) Up to his days the hammer used to strike in Jerusalem,
4) And in his days there was no need to inquire about doubtfully tithed produce.
Section one: As we learned above in mishnah 7:1, twice in seven years a person must take his accumulated tithes out of his house and make a confession at the Temple that he had no more tithes. Yohanan the high priest ended this practice. There are two explanations given for why he ended the practice. The first is that he saw that people were no longer separating tithes, and they were only separating terumah. The second is that the tithes were no longer given to the Levites but rather to the priests. This is because when Ezra came to Israel from Babylonia, the priests did not come with him. Therefore he penalized them by giving the tithes to the priests.
Section two: Before Yohanan the high priest, there was a custom that when the Levites would rise in the Temple in the morning, they would recite the verse, Rouse Yourself; why do you sleep, O Lord? (Psalms 44:24). These Levites were called the wakers. The practice was abolished because it gives the impression that God is sleeping, and Psalms 121:4 says, See, the guardian of Israel neither slumbers nor sleeps.
The knockers refers to a practice of striking a sacrificial heifer between its horns in order to prepare it for sacrifice. This would make it easier to slaughter. When they began to fear that this would render the animal unfit to eat and therefore they stopped the practice.
Section three: Up until the days of Yohanan the high priest, on the intermediate days of the festival (hol hamoed), one could hear the sound of hammers striking in Jerusalem. Although the people were doing the types of work which are permitted on these days (we shall learn these laws when we learn tractate Moed Katan), Yohanan the high priest said that this was inappropriate for the sound made it seem as if there was no festival. Therefore, he put an end to the practice.
Section four: Doubtfully tithed produce (demai) is produce bought from an uneducated person, a person who may not properly separate tithes. In the time of Yohanan the high priest, a person did not need to ask if what he was purchasing was properly tithed, for Yohanan decreed that anybody who buys produce from an uneducated person should separate only the terumah taken from the tithe and second tithe. He would also separate the first and second tithe but these he could eat them himself. Since these tithes may have already been taken out before he bought the produce, the Levite cannot prove that the first tithe belongs to him, nor can the poor person prove that the poor tithe belongs to him. Therefore, he can retain these tithes for himself. Before Yohanans time, people had to ask those selling produce if it was tithed, and they would have to decide whether the person was trustworthy. If the seller was not trustworthy, people wouldnt buy from him, because they would have to separate all of the tithes.