six hundredth and first year: i.e. of Noah's life.
the first month, the first day. Six such important dates in Bible: (1) Here, the drying up of the waters (Gen_8:13); (2) The setting up of Tabernacle by Moses (Exo_40:2); (3) The sanctification of cleansed-up Temple by Hezekiah (2Ch_29:17); (4) The going up of Ezra (Gen_7:9); (5) The giving up of strange wives (Ezr_10:17); (6) The offering up of a bullock in Ezekiel's future Temple (Eze_45:18).