The following quote is from Self-Reliance by Ralph Waldo Emerson:
The doctrine of hatred must be preached as the counteraction of the doctrine of love when that pules and whines.
I don't understand this structurally. What does the when clause explain? I don't really understand the meaning, either.
Breaking it down:
The doctrine of love "pulses and whines" meaning it makes its presence known in "fits and starts" - or intermittently.
Because the love is making itself known, there will be a counter-response, namely that hatred will be preached.
As such, the when clause is acting as an adverb, explaining the circumstances under which the doctrine of hatred is being preached in response to the doctrine of love. Were love to be silent and not affecting anything, there would be no need for a counter response.