1:23a Greek: τη πιστει = the faithfulness. The usage of the article here falls under what is called "the Article with Abstract Nouns...In translating such nouns, the article should rarely be used" (An Exegetical Syntax of the New Testament, Daniel B. Wallace, pg. 226). BDAG 3rd edition, "πιστις...faithfulness, reliability, fidelity, commitment" (pg. 818). The article is used to make definite the kind of faithfulness meant—faithfulness to Messiah Yeshua by walking in His commandments.
1:23b in connection to = εν. This is an abstract use of the Greek word εν, similar to such usage of ב or ל in Hebrew. See BDAG, 3rd, "8...in connection with" (pg. 329).
1:23c "is proclaimed" —aorist passive participle. The mistake of regarding the aorist as an exclusive past tense has led to the nonsense of this text being translated "was proclaimed". To give the non-scholar an analogy, it is similar to claiming that the English "-ed" ending always makes something past tense. Clearly it does not, especially when used in passive examples, "He is being kicked". Notice the "-ed" on kicked?
1:23d The Greek word may mean either "creation" or "creature". Paul's statement is all inclusive. The good news is proclaimed to "all creation", including all creatures in creation. The good news is not just a message of deliverance for the believer from the bondage of the fall. It is also for all creation, which is to be delivered from the results of the fall in the kingdom of the Almighty. That is to say, the good news being proclaimed is targeted not just at fallen man, but at all creation.
Unbelievers are concerned about environmentalism, and are worried that the world is being destroyed. They need to learn that this is because of the fall, and that the final deliverance of the creation can only come through Yeshua the Messiah. The good news is indeed the only hope for the earth.