Q: According to a report, Abdullah bin Abbas (radhiyallahu anhuma), a companion of the Prophet (Sallallahu Alaihi Wasallam) said that triple talaq in one sitting was considered as only one talaq during the Prophet’s (Sallallahu Alaihi Wasallam) time, the period of the first caliph Abu Bakr (radhiyallahu anhu) and during the early years of the second caliph Umar (radhiyallahu anhu) (Sahih Muslim, 1482).
Once Rukanah bin Yazid (radhiyallahu anhu), a companion of the Prophet (Sallallahu Alaihi Wasallam), had divorced his wife thrice in one sitting. Regretting what he had done, he approached the Prophet (Sallallahu Alaihi Wasallam), who asked him how he had divorced his wife. Yazid answered that he had done so by pronouncing the word talaq thrice. The Prophet (Sallallahu Alaihi Wasallam) asked him if he had pronounced it in a single sitting, to which he replied in the affirmative. The Prophet (Sallallahu Alaihi Wasallam) then said that it had the effect of one divorce and that he could take his wife back.
Please explain the above how three talaqs in in sitting was known as one in the prophet Muhammad (Sallallahu Alaihi Wasallam) time and now its taken as three.