According to Luke Chapter One Jesus was conceived six months after the conception of John the Baptist and was born nine months later in the months of September/October according to the Lunar Jewish Calendar.
King David on God's instructions (1 Chr 28:11-13) had divided the sons of Aaron into 24 groups (1 Chr 24:1-4), to setup a schedule by which the Temple of the Lord could be staffed with priests all year round in an orderly manner. After the 24 groups of priests were established, lots were drawn to determine the sequence in which each group would serve in the Temple. (1 Chr 24: 7-19). That sequence is as follows:
1 Chr 24:7 |
1. Jehoiarib |
2. Jedaiah |
1 Chr 24:8 |
3. Harim |
4. Seorim |
1 Chr 24:9 |
5. Malchijah |
6. Mijamin |
1 Chr 24:10 |
7. Hakkoz |
8. Abijah |
1 Chr 24:11 |
9. Jeshuah |
10. Shecaniah |
1 Chr 24:12 |
11. Eliashib |
12. Jakim |
1 Chr 24:13 |
13. Huppah |
14. Jeshebeab |
1 Chr 24:14 |
15. Bilgah |
16. Immer |
1 Chr 24:15 |
17. Hezir |
18. Aphses |
1 Chr 24:16 |
19. Pethahiah |
20. Jehezekel |
1 Chr 24:17 |
21. Jachim |
22. Gamul |
1 Chr 24:18 |
23. Delaiah |
24. Maaziah |
1 Chr 24:19 These were the orderings of them in their service to come into the house of the LORD, according to their manner, under Aaron their father, as the LORD God of Israel had commanded him.
Now each one of the 24 "courses" of priests would begin and end their service in the Temple on the Sabbath, a tour of duty being for one week (2 Chr 23:8, 1 Chr 9:25). On three occasions during the year, all the men of Israel were required to travel to Jerusalem for festivals of the Lord, so on those occasions all the priests would be needed in the Temple to accommodate the crowds. Those three festivals were Unleavened Bread, Pentecost, and Tabernacles (Deut 16:16).
The Yearly Cycle of Service in the Temple.
The Jewish calendar begins in the spring, during the month of Nisan, so the first "course" of priests, would be that of the family of Jehoiarib, who would serve for one week, Sabbath to Sabbath. The second week would then be the responsibility of the family of Jedaiah. The third week would be the feast of Unleavened Bread, and all priests would be present for service. Then the schedule would resume with the third course of priests, the family of Harim. By this plan, when the 24th course was completed, the general cycle of courses would repeat. This schedule would cover 51 weeks or 357 days, enough for the lunar Jewish calendar (about 354 days). So, in a period of a year, each group of priests would serve in the Temple twice on their scheduled course, in addition to the 3 major festivals, for a total of about five weeks of duty.
The Conception of John the Baptist.
Back to Zachariah, the father of John the Baptist, which is important to understand that Jesus was born September/October according to the Lunar Jewish Calendar being conceived six months after John the Baptist.
Luke 1:23 And it came to pass, that, as soon as the days of his ministration were accomplished, he departed to his own house.
Luke 1:24 And after those days his wife Elisabeth conceived
Beginning with the first month, Nisan, in the spring (March-April), the schedule of the priest's courses would result with Zachariah serving during the 10th week of the year. This is because he was a member of the course of Abia (Abijah), the 8th course, and both the Feast of Unleavened Bread (15-21 Nisan) and Pentecost (6 Sivan) would have occurred before his scheduled duty. This places Zachariah administration in the Temple as beginning on the second Sabbath of the third month, Sivan (May-June).
Having completed his Temple service on the third Sabbath of Sivan, Zachariah returned home and soon conceived his son John. So John the Baptist was probably conceived shortly after the third Sabbath of the month of Sivan.
