"Gird up your loins" is a Hebrew idiom for "get ready for action" (cf. Exod. 12:11; 1 Kgs. 18:46; 2 Kgs. 4:29; 9:1; Eph. 6:14; 1 Pet. 1:13), which would be similar to our "roll up your sleeves."
"Girding up his loins" meant to pull one's robe through the legs to the front and tuck it into the sash, thereby forming tight-fitting shorts, ready for action.
This phrase is also used in a figurative sense of "protect your mind." The rabbis saw the mind as a garden ready for seed. Whatever we allow to reach the mind through sight or hearing, becomes what we think about. If we dwell on that topic, we will surely act on that topic. Protect your mind (1 Pet. 1:13-16).
The Holy Spirit is with us but we must participate in allowing Him to protect and guide us!
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