New Defender's Study Bible Notes
9:24 Seventy weeks. The word for “weeks” is actually “sevens;” in the context, it obviously means “seven-year periods.” Daniel had been meditating on God’s promise that the captivity of his people would be seventy years, but then Gabriel brought the message that, not just seventy years, but seventy sevens of years, were determined on his people. That is, God would be dealing with Israel as His covenant people for a period of 490 years. The events prophesied for these 490 years are critical for the proper understanding of eschatology and prophecy. Furthermore, the remarkable fulfillment of the key portions of the prophecy of the seventy weeks is certainly one of the strongest evidences for the supernatural inspiration of Scripture.
9:24 finish the transgression. Much of the prophecy has been fulfilled, but not all. Its complete accomplishment (e.g., “an end of sins,” “everlasting righteousness”) awaits the second coming of Christ. Consequently, since far more than 490 years have already passed, there must be at least one significant gap implied in its development. This seems to be clear in the following verses. However, many eminent expositors have understood it as an unbroken sequence, terminating in the first coming and death of Christ.