This phrase is the first of two participial phrases Peter uses to describe what his readers need to do in order to set their hope on God’s grace. The terms Peter uses in this phrase awaken in the mind of the reader the picture of a man wearing the traditional long robe of that era but picking up its bottom and tucking it into his belt so that he can run freely. Peter’s reference, however, is not to a literal robe but to one’s mind. The reality is that there is often so much clutter in the mind that hinders undivided focus on the inheritance we are receiving (like too much clothing around your legs can hinder easy running). In his parable of the sower, the Lord Jesus gives examples of this mental clutter (Matthew 13:7, Matthew 13:22).
13 Therefore, preparing your minds for action, and being sober-minded, set your hope fully on the grace that will be brought to you at the revelation of Jesus Christ.