23. Nothing is more common in the Word than for the word 'day' to be used to mean the particular time at which events take place, as in Isaiah,

The day of Jehovah is near. Behold, the day of Jehovah comes. I will make heaven tremble, and the earth will be shaken out of its place, on the day of My fierce anger. Its time is close at hand, and its days will not be prolonged. Isaiah 13:6, 9, 13, 22.

And in the same prophet,

Her antiquity is in the days of antiquity. On that day Tyre will be forgotten for seventy years, like the days of one king. Isaiah 23:7, 15.

Since 'day' stands for the particular time it also stands for the state associated with that particular time, as in Jeremiah, Woe to us, for the day has declined, for the shadows of evening have lengthened! Jeremiah 6:4

And in the same prophet,

If you break My covenant that is for the day and My covenant that is for the night, so that there is neither daytime nor night at their appointed time. Jeremiah 33:20, 25.

Also,

Renew our days as of old. Lamentations 5:21.

8400. 'On the fifteenth day of the second month' means this state considered in relation ... This is clear from the meaning of the number 'fifteen', from the meaning of 'day', and from the meaning of 'month'. 'Month' means the end of the previous state and the beginning of the next, thus a new state, 3814; 'day' means a state in general, 23, 487, 488, 493, 893, 2788, 3462, 3785, 4850, 7680, and 'the fifteenth' means that which is new. For 'fourteen days' or two weeks mean a whole period or state from the beginning to the end of it, 728, 2044, 3845; 'fifteen' therefore means something new, in this instance newness of life, meant by the manna which they received from heaven, 'manna' being the good of truth, which is the life of a spiritual person. Fifteen is similar in meaning to eight, because the eighth day is the first day of a following week. For the meaning of 'the eighth day' as any beginning whatever, thus something new that is distinct and separate from what has gone before, see 2044, 2866; and for the fact that all numbers in the Word have spiritual realities as their meaning, 482, 487, 575, 647, 648, 755, 813, 1963, 1988, 2075, 2252, 3252, 4264, 4495, 4670, 5265, 6175.