Q. How can we have two lists of months, one beginning from Tishri, the month of Rosh HaShanah, and one from Nisan, the month of Pesach?
The other is universalistic and commences with the creation of the whole world on Rosh HaShanah.
At one and the same moment we are members of our own people and members of the human race. Hence the prayer book for Pesach concentrates on the history and destiny of Israel and the prayer book for Rosh HaShanah looks at the whole of mankind and speaks of God judging all the peoples and all the nations.
The contrast between them is illustrated by the fact that on Pesach we are part of a record of events; on Rosh HaShanah it is not so much time but traits that are on our liturgical agenda.