(A verse-by-verse study from a NCT perspective.)
2 According to the foreknowledge of God the Father, by the consecration of the Spirit, for obedience and sprinkling of the blood of Jesus Christ. Grace to you and peace be multiplied.
The apostle included one more adjective in his description of his audience in verse 1 (some translations transfer it to verse 2) when he called them elect. To be elected is to be selected, or chosen, or specifically picked out of a group. So Peter is indicating that out of all the people living in Pontus, Galatia, etc., the believers were specifically selected.
But on what basis and by whom was this selection made? By the foreknowledge of God the Father, by the consecration of the Spirit. God was the selector; He made the choice about who would follow Christ and who wouldn't. And He did it in agreement with His divine foreknowledge.
Peter spoke of God's foreknowledge on another occasion when he explained to the Jews how they had killed the Messiah (Acts 2:23). The death of Jesus, he said, was performed by the Romans at the request of the Jews. But even those causes were the outworking of an ultimate, prior cause—God. God is ultimately responsible for putting His Son on the cross, and He did so according to His predetermined plan and His foreknowledge. In the same way, those who would receive the gospel have been pre-determined by God's plan and foreknowledge. He knows the elect in a way that He does not know the non-elect.
Although their external appearance may not cause them to stand out from any other humans in Asia Minor, to be sure the Christians were different. Their uniqueness came from the fact that the Spirit of God had set them apart from unbelievers (cp. 2 Thess. 2:13). They were special to God, sanctified unto Him for a specific purpose—obedience and sprinkling of the blood of Jesus Christ.
Again, the apostle borrows Jewish imagery to convey truth. Sprinkling the blood of sacrificial animals was an expression of consecration under the Old Covenant. In fact, at the very establishment of the covenant, as Moses read its stipulations, he took blood from the bulls and sprinkled it on the people of Israel (Exo. 24:7, 8). As a consequence, they had been set apart and made partakers of this special relationship to God. (See also the consecration of the Most Holy Place in Lev. 16; Heb. 9:18f.). Likewise, believers are made partakers of the New Covenant through the blood (Jesus') of that covenant, (Luke 22:20; Heb. 9:13f.) the everlasting covenant (Heb. 13:20).
The obedience spoken of here may be ongoing submission to Christ or initial submission to Christ at the time of repentance and conversion. Although I would not want to wrangle too much about this, I prefer the latter because of the tie with the blood consecration already spoken of. For a similar use of 'obedience' see Rom. 1:5 and 16:26.
Grace and peace to you is a standard greeting in the New Testament, but it must not be relegated to a place of mere formality. If there are two things all believers of all cities of all generations need, they are God's grace and peace. The words may be routine, but the sincerity of the request should not be questioned.