Here are excerpts from R. Lusk (a current “member” of the Federal Vision) and T. Beza (a second generation Reformer, d. 1605). Read carefully, and note the most important term, instrument (cf. Belgic Confession, 22 or WCF 11.2). I’ve bolded instrument below for ease of reference.
“In other words, works do not justify in their own right since they can never withstand the scrutiny of God’s inspection. But we will not be justified without them either. They are not merely evidential (e.g., proof of our faith), but even causal or instrumental (“means”) in our final salvation.” Go here for the full article and context.
“Faith” is the “the sole instrument by which we take hold of Jesus Christ when He is offered to us, the sole vessel to receive Him.” Further, “When therefore, after St. Paul (Rom 1: 17; 3:21-27; 4:3; 5:1; 9:30-33; 11:6; Gal 2:16-21; 3:9,10,18; Phil 3:9; 2 Tim 1:9; Titus 3:5; Heb. 11:7) we say that we are justified by faith alone, or freely, or by faith without works (for all these ways of speaking give the same sense), we do not say that faith is a virtue which makes us righteous, in ourselves, before God. For this would be to put faith in the place of Jesus Christ who is, alone, our perfect and entire righteousness.” Go here for the full booklet and context.
In summary, Lusk’s understanding of instrument is at odds with Calvin’s successor, T. Beza. Beza says one instrument while Lusk says more than one.