At a recent singing I attended, before leading Farther Along, a man told that singing this as a child he heard and thought it was "Father, alone, will know all about it; Father, alone, will understand why..." rather than "Farther along we'll know all about it, Farther along we'll understand why." In language/grammar this is called a mondegreen -- repeating the mishearing of a phrase in such a way that it acquires a new meaning.
Some misunderstood songs are misunderstandings of a word's meaning. Many a child not raised on a farm* have envisioned sheep being brought in to the fold as they sang "Bringing in the sheaves". But that is "sheaves" -- bundles of grain -- rather than the plural of sheep (which is sheep).
Readers, as a child did you ever misunderstand some song or songs, either mishearing the phrase or misunderstanding a meaning? Tell us about it.
*And I can testify for those raised on a farm which didn't harvest wheat. The only things I think we bundled were put up in bales (hay) or shocks (corn).