Daniel 7:9-14 and 8:14 refer to the cleansing of the heavenly sanctuary during the antitypical Day of Atonement. This cleansing of both sanctuary and people is the pre-advent judgment.
The phrase translated "days" (KJV) means a 24-hour period. The Hebrew phrase is ereb boqer. It means literally "evening-morning." Some form of this phrase is used 22 times in the Hebrew Old Testament. When a 24-hour period is intended, the phrase is always "evening-morning," never "morning-evening." (See Gen. 1:5, 8, 13, 19, 23, 31.) In Daniel 8:14, 26 the phrase is "evening-morning," a 24-hour period. The reference in Daniel 8:14 is not to the morning evening sacrifices of the sanctuary, but to 2300 24-hour days that are used as a prophetic symbol.
The 2300 literal days of Daniel 8:14 are symbolic of 2300 years. The prophet was told that the work of the little-horn power would continue till the end of time (Dan. 8:17,19,25,26). Twenty-three hundred literal days (about 6 years and 4 months) would not reach to the end of time.
The relationship between Daniel 8 and 9 reveals that the 2300 days are years and provides us the beginning date for the period. The vision of Daniel 9 was given in 538 B.C., 13 years after the vision of Daniel 8 (551 B.C.). Gabriel told Daniel that "seventy weeks" (Hebrew: "seventy sevens") were to be "cut off" (Hebrew: hathatk) from the 2300 days. These "seventy sevens" must refer to 490 years, because they were to reach to the time of the Messiah. Because 490 years cannot be cut off from 2300 literal days, the days must be a prophetic symbol of 2300 days.
What was the beginning date for the 2300 years (Daniel 8:14) and the 490 years (Dan. 9:24)? Both periods were to begin with the going forth of the commandment to restore and build Jerusalem (Dan. 9:25). Ezra 6:14 indicates that three human decrees enacted God's decree. The decree of Artaxerxes I was certainly put into operation in 457 B.C. Twenty-three hundred years later, in A.D. 1844, the cleansing of the heavenly sanctuary, the antitypical Day of Atonement, the pre-advent judgment, began.