By Rabbi Berach Steinfeld
The Torah tells us that the Yidden were counted in Parshas Ki Sisa, Posuk tes zayin. Rashi says the number of Yidden that were counted in Ki Sisa, which took place after Cheit HaEigel, and the number of Yidden that were counted on Rosh Chodesh Iyar mentioned in beginning of Parshas Bamidbar, which was after the building of the mishkan, was one and the same. The people being counted were the exact same people and therefore the amount ended up identical. How could it be that there weren’t any people who turned twenty during the tekufah from the day after Yom Kippur until Rosh Chodesh Iyar? We could explain that people were considered twenty only after the Rosh Hashana following their birthday. If so, it would be very understandable why the first count which took place after Yom Kippur and the second count which took place a half a year later on Rosh Chodesh Iyar resulted in the exact same amount of people. This fits in very well with the Rashi at the beginning of Parshas Bamidbar that explains the reason for the Yidden being counted a second time was because Hashem was showing his love to them. Despite the fact that the number did not change, Hashem commanded them to be counted again.
The Ramban in Parshas Ki Sisa argues and says why should Rosh Hashana decide when a person gets to be considered the next age? A person should rather be counted based on his birthday. The question therefore arises, why was the second count the same amount as the first count? The Ramban answers that the first count in Parshas Ki Sisa included Sh
The above pshat is very meduyak in the posuk because in the count of Parshas Bamidbar the posuk
This also fits in well with why the Leviim were not eligible to be in the army, since the Leviim worked in the Bais Hamikdosh. We find that Hashem told Dovid Hamelec
May we be zocheh to have the Bais Hamikdash re-built and we should not be involved in any more wars.