Here the word "you" refers to Yahweh. The word "life" represents the person. Alternate translation: "you have saved me from death" or "you have kept me from dying" (See: [[rc://en/ta/man/translate/figs-metonymy]])
The feet here represent the person. Stumbling here probably represents being killed by his enemies. Alternate translation: "you have rescued me from stumbling" or "you have kept me from being killed by my enemies" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-metaphor]])