The feet here represent the person. Stumbling here probably represents being killed by his enemies. Alternate translation: "you have kept me from stumbling" or "you have kept me from being killed by my enemies" (See: [[rc://en/ta/man/jit/figs-synecdoche]])
Living and being seen by God is spoken of as walking before God. Alternate translation: "so that I may live in God's presence" (See: [[rc://en/ta/man/jit/figs-metaphor]])
Here "the light of the living" probably represents God's enabling people to live. Alternate translation: "with the life that you give" or "because you enable me to live" (See: [[rc://en/ta/man/jit/figs-metonymy]])