Bede

Now it happened in the month of Nisan, etc. Nisan is the first month of the year according to the Hebrews, in which they always used to celebrate Passover, which we call April. Therefore, what was said above, that he mourned, fasted, and prayed for many days, it is evident indeed that for four continuous months, namely the ninth, tenth, eleventh, and twelfth, he devoted himself to this most sacred dedication, awaiting the opportune time in which he could express his desire to the king. …

Commentary on Ezra and Nehemiah ↗