Ephesians 6:15

Roman infantrymen wore tough sandals studded with sharp, thick nails on the bottoms to increase traction. [Note: Josephus, The Wars . . ., 6:1:8.] The gospel that has brought peace to the Christian enables him or her to stand firmly against temptation. Likewise the gospel is what enables us to move forward against our enemies (cf. Isaiah 52:7). The preparation of the gospel of peace probably refers to the gospel the Christian soldier has believed that enables him to stand his ground when attacked. We must be so familiar with the gospel that we can share it with others (cf. 1 Peter 3:15). That grip on the gospel will enable us to hold our ground and even advance when tempted. The gospel in view is the whole Christian message viewed as good news, not just how to become a Christian.

". . . protection comes from reflecting the unity that the gospel provides within the community (’shod your feet with the preparation of the gospel,’ Ephesians 6:16 [sic, Ephesians 6:15], looks back to Ephesians 2:11-22; it is not a reference to evangelism)." [Note: Bock, "A Theology . . .," p. 318.]