Dan 9.24 “Seventy ‘sevens’ are decreed for your people and your holy city to finish transgression, to put an end to sin, to atone for wickedness, to bring in everlasting righteousness, to seal up vision and prophecy and to anoint the Most Holy Place.
Israel's rebellion against God reached its apex when they rejected Christ. This brought Israel's final Sin, for which she was to be judged throughout the NT era, to an end. To judge Israel was to "finish transgression." It *ended sin* in Israel by deporting the population, which is how God had dealt with Israel's apostasy under the Law.
Israel's sin of rejecting Christ would be judged, bringing Israel's place as a Nation of God to an end. They would be cast into exile, and their nation would cease to exist. This brought an end to their sin, at least in the land of Israel.
Part of "atoning for sin" is in offering a proper remedy against the perpetrators. In this case, Israel was the perpetrator, and Christ's death spelled their Sin in its most awful way, though as a means of reconciliation back to God. Though this took place only for the few who accepted him the way was provided for the ultimate reconciliation of all Israel with God.
To make things right after Israel's rebellion in rejecting Christ, their sin had to be removed, to be replaced with a righteousness that would last. Israel's righteousness had not lasted, however. Only Christ's righteousness existed as the means of restoring Israel to righteousness. In providing Eternal Life along with his own righteousness, and by giving this righteousness to his disciples, Jesus provided a righteousness that would last forever. By virtue of his resurrection from the dead, Christ's righteousness remains available to Israel and to all men with faith by accessing his Spirit.
Christ himself sealed up vision and prophecy by becoming the promised means of Israel's future Salvation. He had to do this by 1st bringing Israel into judgment. Later, those few who accepted him would be given positions of authority over the nation to bring it back into conformity with righteousness. The Messianic prophecies Jesus fulfilled were on behalf of the Finished Work of Atonement he came to supply. It did not, however, mean that God's promises had been completed for Israel and for the world--only the means by which these things could be accomplished were provided for at that time.
Given that the "Holy Place" of the temple was to be destroyed, as predicted by Christ as a judgment against Israel, he himself became the anointing of the temple by declaring himself the heavenly temple, one that would never be destroyed. He anointed the most holy place by presenting himself at God's temple in heaven, anointing it as the future place where God would forever dwell with Israel and with all believers.