What time they wax warm, they vanish: when it is hot, they are consumed out of their place.
Wax warm - rather, 'At the time when (But they soon, Umbreit) they become narrower (flow in a narrower bed-literally, are bound: akin to a Syriac root), they are silent (cease to flow noisily); in the heat of the sun they are consumed (or vanish) out of their place.' First the stream flows more narrowly-then becomes silent and still: at length every trace of water disappears by evaporation under the hot sun (Umbreit). But Maurer translates like English version, 'What time they are burnt up' - i:e., dried up with summer heat х zaarab (H2215) - the same as tsaarab (H6866) and saarap (H8313), to burn], 'they are destroyed speedily.' The parallelism supports this.