That (hopōs). Rather than the more common final particle hina. Connected with mneian poioumenos.
The fellowship of thy faith (hē Koinéōnia tēs pisteōs sou). Partnership like Phi 1:5 in (objective genitive, pisteōs).
Effectual (energēs). Common adjective, like energos (at work), in N.T. only here, 1Co 16:9; Heb 4:12. Papyri use energos of a mill in working order, of ploughed land, etc.
In you (en humin). Some MSS. have en hēmin (in us), itacism and common.