"everyone was unsure what to think about John; they asked themselves, 'Could he be the Christ?'" or "no one was sure what to think about John because they were wondering whether he might be the Christ."
John's answer about a greater person coming clearly implies that John is not the Christ. It may be helpful to state this clearly for your audience. AT: "John clarified that he was not the Christ by saying to them all" (See: [[rc://en/ta/man/translate/figs-explicit]])
"not important enough even to loosen the straps of his sandals." Untying the straps of sandals was a duty of a slave. John was saying that the one who would come is so great that John was not even worthy enough to be his slave.
This metaphor compares literal baptism that brings a person into contact with water to a spiritual baptism that brings them into contact with the Holy Spirit and with fire. (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here the word "fire" may refer to 1) judgment or 2) purification. It is preferred to leave it as "fire" (See: [[rc://en/ta/man/translate/figs-metaphor]])
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