Unquote #2 answer

The quote

Nothing will ever be attempted if all possible objections must be first overcome.

The puzzle as it was set

MFLYBMD UBJJ QSQV WQ ILLQHCLQP BK IJJ CFAABWJQ FWRQZLBFMA HEAL WQ KBVAL FSQVZFHQ.

The key

Each code letter stood for one real letter (code letter, then the real letter it hid):

I → AW → BZ → CP → DQ → EK → FD → GY → HB → IR → JJ → LH → MM → NF → OC → PV → RA → SL → TE → US → VU → W

The most frequent code letter was Q (10 times), which stood for E. Short words, apostrophes and repeated letters are the usual way in: a one-letter word is almost always A or I, and THE is the commonest three-letter word in English.