Literal translation
he who builds on gravel wastes his time and his effort
Meaning
build on gravel and you waste your time and effort
Explanation
This saying warns against undertakings founded on fragile or unstable ground, drawing on the very concrete image of a building set on gravel, with no solid foundation. The words to build, on, gravel, time, and effort are all well attested, this last term properly meaning to labour, to take pains, used here in the sense of effort spent in vain. The verb rendered as to lose, however, could not be found directly in our sources under this exact form. The image of gravel, loose and unstable ground that does not hold foundations, contrasts with the idea of firm soil on which one could build lastingly: building on such ground exposes one, sooner or later, to the collapse of the structure, whatever the quality of the work otherwise put into it. By extension, the saying applies to any undertaking, life project, or relationship founded on superficial or poorly secured grounds, doomed to fail despite the effort invested. The register is sententious and moralising, typical of sayings of practical wisdom.