Below is one explanation I found for why the "seven weeks" would be separated from, and precede, the 62, but it seems like a reach to find significance in the seven:
Like you, I have often mused before on the significance of why this first period of 7 weeks (49 years) is separated from the other 62 weeks which directly follow it (another 434 years). The answer I think is typically one from Jewish law. I'd appreciate it if you could offer some comments either pro or con to the following proposal.
I suggest that this 49 years from when the decree was first given was
that point in time at which the high priest died in post-exilic Jerusalem. There was real significance for marking this date, and it mirrors the results of Christ's death (which was included in the 70th week). In other words, Daniel's 70-week prophecy
begins with the death of a high priest at the end of the 7 weeks period, and then
ends with the death (and resurrection) of the Great High Priest - Jesus the Messiah - in the period of the last 70th week.
Back in the OT, when someone accidentally caused the death of a person, he would flee to one of the "cities of refuge" where he would be required to live
until the death of the high priest (Numbers 35:9-28). Once the high priest died, the "avenger of blood" could no longer have a claim of vengeance on the one who had killed their relative accidentally, and the manslayer could return to the land of his possession again without risk of being killed by the avenger. This was a precursor to the spiritual benefits we receive from Christ's death. When that happened, we could spiritually "return to the land of our possession" in fellowship with God, because our offenses were wiped clean by the death of our Great High Priest.
If I'm reading the regulations correctly, the high priest was chosen to serve, (like the Levites who waited upon the service of the tabernacle of the congregation), from the age of 25 (Numbers 8:24-25). If we add the 49 years of Daniel's first 7-week period to a high priest's term of service beginning at age 25, that means the high priest would have died at 74 - a not unreasonable age for this.
Now, we are told that Joshua the son of Josedech was anointed to serve in the post-exilic temple in Jerusalem. If he was 25 when he began to serve in the high priest's office, then I propose the 49 years later might very well have marked the death of Joshua the high priest at the age of 74.
Comments?