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18 And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.
"Birds" represent rational concepts in the external man and intellectual concepts in the internal man.
16 Three times in a year shall all your males appear before Yahweh your God in the place which he shall choose: in the feast of unleavened bread, and in the feast of weeks, and in the feast of tents; and they shall not appear before Yahweh empty: