Our Priest greets us by extending his arm in a welcoming gesture. It "signifies the presence of the Lord to the Assembled Community" (GIRM) as Jesus said, "for where two or three are gathered together in my name, I am there among them" (Mt 18:20).
Our Priest may then say any of the three options below:
The grace of our Lord Jesus Christ, and the love of God, and the communion of the Holy Spirit be with you all.
Grace to you and peace from God our Father and the Lord Jesus Christ.
The Lord be with you.
Our Reply: and with your spirit