“ Higher wages are never a cause for higher profits, although they may be one of the consequences of higher profits during some particular phases of the industrial cycle. ”
 Karl Marx, Das Kapital (1894). copy citation

Context

“The industrial capitalist invests it in means of production and in labour-power. The rising demand for labour-power can never by itself be a cause for a rising rate of interest, in so far as the latter is determined by the rate of profit. Higher wages are never a cause for higher profits, although they may be one of the consequences of higher profits during some particular phases of the industrial cycle. The demand for labour-power can increase because the exploitation of labour takes place under especially favourable circumstances, but the rising demand for labour-power, and thus for variable capital, does not in itself increase the profit;” source