11 Now may our God and Father Himself, and our Lord Jesus Christ, direct our way to you.
12 And may the Lord make you increase and abound in love to one another and to all, just as we do to you,
13 so that He may establish your hearts blameless in holiness before our God and Father at the coming of our Lord Jesus Christ with all His saints.
direct (v.11) — singular, indicating (perhaps) the divinity of Jesus Christ and His unity with the Father. Even if we shouldn’t read that much into the singular here, it’s still a fact that Paul was directing his prayer to the Father and to Jesus Christ.
and (1st use, v.12) = but — whether Paul came to them or not
increase and abound in love (v.12) = “to be enlarged and to exceed, to go beyond” — Philippians 1:9
love (v.12) = agape
to one another and to all (v.12) — to the Christians in the church and to all other people
so that (v.13) — when they get to the point where they have agape love for all, their hearts will be blameless in holiness
establish (v.13) = fix firmly, strengthen, support
blameless (v.13) — no charge against them could be maintained
saints (v.13) = lit. “different,” holy ones. Some commentators think it refers to angels in this context (2 Thessalonians 1:7). The word “saints” also seems to refer to angels in Jude 1:14
Stam has a different take:
But how can His coming for us be “the coming of our Lord Jesus Christ with all His saints”? The answer is again found in the simple fact that the word parousia (rendered both as “coming” and “presence”) refers here to His “presence … with all His saints.” Thus we find a further reference to the rapture of the members of the body of Christ to be with Him. — Stam, page 51.
I’m not yet sure which view I take.