Originally Posted by diffangle
This was a really good question.
From what I gathered from the previous verses, the 4 men that Paul accompanied to the temple had taken a Nazirite vow. Nazirites were required to offer a sacrifice and shave their heads after their days of consecration were completed.
You will notice that in verse 26, it never really states that the sacrifice was actually made...It just tells us that this would be the time at which they would have made the sacrifice.
At the time this took place, the Jews were still following all of the rituals set forth by Mosaic law and customs. Ritualistic Law was still ingrained in Judaism, and either way, the Nazirites were still required to shave their heads and make atonement after their days of purification.
What I get from this account, the elders were complaining to Paul re: the Jewish zealots, who still swore by the Law. After Paul informed them of God's ministry to the Gentiles, the elders basically told Paul to go to the temple and inform the Jews that, although they were not following the ritualistic aspects of the Law, that they were still "walking orderly and keeping the Law." The fact that God could do this kind of work amongst the Gentiles, who did not abide by the Jewish rituals, just proves that Jesus' sacrifice had taken the place of the Law.
You must realize that this account never states that the sacrifices were made, or that Paul even had any intention of making those sacrifices. All it is saying is that this would have been the time the sacrifices were made, according to Jewish custom. To bring 4 Nazirites to the temple may have been Paul's way of proving his point.