Here "the word of your lips" is a metonym for God's instruction, and "the ways of the lawless" is a metaphor for the things that lawless people do. AT: "it is by obeying your instruction that I have kept myself from doing the things that lawless people do" or "your instruction has caused me to avoid doing wicked things" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])
Both of these clauses mean the same thing. The repetition adds emphasis. (See: [[rc://en/ta/man/translate/figs-parallelism]])
# my feet have not slipped
The writer speaks of his obedience to God as if he were walking on a path. AT: "I am determined to follow your ways" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-litotes]])