How many times did Moshe go up on Mount Sinai after the Decalogue and for how long did he go each time? Also, were these ascents consecutive or was there a break between them?
The book of Shemot seems to record that Moshe went up three times to Mount Sinai. Shemot 24:16,18 record that Moshe went up to Mount Sinai for forty days, and then Shemot 32:15 records that Moshe came down with the tablets. Afterwards, Shemot 33:20 (see Rashi on Devarim 9:18) seems to imply that Moshe went up a second time to Mount Sinai, but there is no mention for how long. Afterwards, Shemot 34:4,28 record that Moshe went up a third time for forty days.
The book of Devarim also seems to record that Moshe went up on Mount Sinai three times. Devarim 9:9,11 record that Moshe went up on Mount Sinai to get the first set of tablets. Afterwards, 9:18, 25 record that Moshe prayed for forty days, but it does not record that Moshe went up on Mount Sinai. Rashi (on 9:25) explains that 9:25 does not refer to a new set of 40 days but refers back to the second set of 40 days. This would be a case of resumptive repetition, where the text repeats itself to resume the narrative. Moshe had been discussing the sin of the golden calf from 9:8-21, but then he digressed to mention other sins of the people beside the golden calf, 9:22-24, so the text repeated itself to return to the incident of the golden calf, 9:25. Afterwards 10:1 records that Moshe was to go up to Mount Sinai to get the second set of tablets, but there is no mention for how long. This ascent corresponds to the third ascent recorded in Shemot 34:4,28. The final reference to being on Mount Sinai is 10:10, which records that Moshe was on the mountain for forty days. One might be tempted to understand that the verse is referring to Moshe's ascent to get the second set of tablets since this verse is recorded after 10:1, but 10:10 also records that “that G-d agreed not to destroy the people,” which is in reference to Moshe's prayers in 9:25. This means the verse is referring to the second set of forty days. If this is true, then 10:10 implies that Moshe went up to Mount Sinai also by the second set of the forty days.
This reading of Shemot 33, 34 and Devarim 9, 10 indicates that Moshe went up to Mount Sinai three times, each time for forty days. Luzzatto (on 9:18) agrees that there were three sets of forty days, but he argues that for the middle forty days, Moshe was not on Mount Sinai since 9:18,25 do not record that Moshe went up to Mount Sinai. Luzzatto brings a proof from Shemot 33:7, which records that Moshe moved his tent outside the camp, and this means that Moshe was not on Mount Sinai. How does he understand Shemot 32:30? I did not see him comment on the verse. Maybe he understands that as Shemot 32:30 just records the words “go up” but no mention is made of Mount Sinai, then “go up” means to separate from the people, which Moshe did in Shemot 33:7, but not that to ascend the mountain. Luzzatto notes that 10:10 seems to contradict his approach, but argues that the verse refers to the last set of forty days.
I think the simple reading of Shemot 32:30 is that for the middle forty days, Moshe was on Mount Sinai, and this is also the implication of 10:10. 10:10 is a continuation of 9:25-29, and is another case of resumptive repetition. Moshe had digressed from the story of the sin of the golden calf to discuss the selection of the Levites, and 10:10 returns to the second set of forty days when Moshe prayed for the people after they had sinned by the golden calf. Accordingly, since 10:10 states that Moshe was on Mount Sinai, then this means that also by the second set of forty days Moshe went up on Mount Sinai. However, Luzzatto has a strong proof that Shemot 33:7 and the ensuing conversation, 33:12-23, between G-d and Moshe could not have been on Mount Sinai. Thus, I think there is a need to offer a different chronology.
My guess is that there was a break in between the second and third sets of forty days. After breaking the tablets, at the end of the first set of forty days, 9:11-17, Moshe went back up to Mount Sinai for a second time, as indicated by Shemot 32:30 and Devarim 10:10, and this ascent was for forty days as indicated by 9:18, 25 and 10:10. After this second set of forty days, Moshe pitched his tent outside the camp and had another conversation with G-d, 33:1-23, but this conversation was not on Mount Sinai. We do not know how long this conversation lasted, a week, a month? At the end of this conversation, Moshe went up to Mount Sinai again, Shemot 34:4 and Devarim 10:1. In Devarim, there is no record of how long this third ascent lasted, but from Shemot 34:28, we know it lasted another 40 days.
With this chronology, Moshe went up to Mount Sinai three times after the Decalogue, each time for forty days, but these ascents were not consecutive. I think this approach gives a consistent reading of the text in Shemot and Devarim. (However, this approach does not accord with the idea mentioned by Rashi on 9:18 that Moshe came down with the second set of tablets on Yom Kippur.)
The book of Shemot seems to record that Moshe went up three times to Mount Sinai. Shemot 24:16,18 record that Moshe went up to Mount Sinai for forty days, and then Shemot 32:15 records that Moshe came down with the tablets. Afterwards, Shemot 33:20 (see Rashi on Devarim 9:18) seems to imply that Moshe went up a second time to Mount Sinai, but there is no mention for how long. Afterwards, Shemot 34:4,28 record that Moshe went up a third time for forty days.
The book of Devarim also seems to record that Moshe went up on Mount Sinai three times. Devarim 9:9,11 record that Moshe went up on Mount Sinai to get the first set of tablets. Afterwards, 9:18, 25 record that Moshe prayed for forty days, but it does not record that Moshe went up on Mount Sinai. Rashi (on 9:25) explains that 9:25 does not refer to a new set of 40 days but refers back to the second set of 40 days. This would be a case of resumptive repetition, where the text repeats itself to resume the narrative. Moshe had been discussing the sin of the golden calf from 9:8-21, but then he digressed to mention other sins of the people beside the golden calf, 9:22-24, so the text repeated itself to return to the incident of the golden calf, 9:25. Afterwards 10:1 records that Moshe was to go up to Mount Sinai to get the second set of tablets, but there is no mention for how long. This ascent corresponds to the third ascent recorded in Shemot 34:4,28. The final reference to being on Mount Sinai is 10:10, which records that Moshe was on the mountain for forty days. One might be tempted to understand that the verse is referring to Moshe's ascent to get the second set of tablets since this verse is recorded after 10:1, but 10:10 also records that “that G-d agreed not to destroy the people,” which is in reference to Moshe's prayers in 9:25. This means the verse is referring to the second set of forty days. If this is true, then 10:10 implies that Moshe went up to Mount Sinai also by the second set of the forty days.
This reading of Shemot 33, 34 and Devarim 9, 10 indicates that Moshe went up to Mount Sinai three times, each time for forty days. Luzzatto (on 9:18) agrees that there were three sets of forty days, but he argues that for the middle forty days, Moshe was not on Mount Sinai since 9:18,25 do not record that Moshe went up to Mount Sinai. Luzzatto brings a proof from Shemot 33:7, which records that Moshe moved his tent outside the camp, and this means that Moshe was not on Mount Sinai. How does he understand Shemot 32:30? I did not see him comment on the verse. Maybe he understands that as Shemot 32:30 just records the words “go up” but no mention is made of Mount Sinai, then “go up” means to separate from the people, which Moshe did in Shemot 33:7, but not that to ascend the mountain. Luzzatto notes that 10:10 seems to contradict his approach, but argues that the verse refers to the last set of forty days.
I think the simple reading of Shemot 32:30 is that for the middle forty days, Moshe was on Mount Sinai, and this is also the implication of 10:10. 10:10 is a continuation of 9:25-29, and is another case of resumptive repetition. Moshe had digressed from the story of the sin of the golden calf to discuss the selection of the Levites, and 10:10 returns to the second set of forty days when Moshe prayed for the people after they had sinned by the golden calf. Accordingly, since 10:10 states that Moshe was on Mount Sinai, then this means that also by the second set of forty days Moshe went up on Mount Sinai. However, Luzzatto has a strong proof that Shemot 33:7 and the ensuing conversation, 33:12-23, between G-d and Moshe could not have been on Mount Sinai. Thus, I think there is a need to offer a different chronology.
My guess is that there was a break in between the second and third sets of forty days. After breaking the tablets, at the end of the first set of forty days, 9:11-17, Moshe went back up to Mount Sinai for a second time, as indicated by Shemot 32:30 and Devarim 10:10, and this ascent was for forty days as indicated by 9:18, 25 and 10:10. After this second set of forty days, Moshe pitched his tent outside the camp and had another conversation with G-d, 33:1-23, but this conversation was not on Mount Sinai. We do not know how long this conversation lasted, a week, a month? At the end of this conversation, Moshe went up to Mount Sinai again, Shemot 34:4 and Devarim 10:1. In Devarim, there is no record of how long this third ascent lasted, but from Shemot 34:28, we know it lasted another 40 days.
With this chronology, Moshe went up to Mount Sinai three times after the Decalogue, each time for forty days, but these ascents were not consecutive. I think this approach gives a consistent reading of the text in Shemot and Devarim. (However, this approach does not accord with the idea mentioned by Rashi on 9:18 that Moshe came down with the second set of tablets on Yom Kippur.)