Logos and Myth

In the previous post, the meaning of myth as "story believed to be true" was discussed. Horrell's emphasis on the "community-forming" power of myth is intriguing since Paul remarks on the powerful and active Logos in 1 Thess 2:13: "We also constantly give thanks to God for this, that when you received the word of God that you heard from us, you accepted it not as a human word but as what it really is, God's word, which is also at work in you believers" (NRSV).

What did Paul mean by "word at work" here? Did he perceive this "word" as something like a myth, and something at work due to its "factual-ness"(that is, God's salvation story through Jesus as a true event)? Did he distinguish Logos from story (diegesis)? Did Paul intend his letters to be "word at work" in any sense? What is the difference between "word preached (gospel)" and Paul general ethical instruction?