39 When work people have recourse to a strike and become voluntarily idle, it is frequently because the hours of labor are too long, or the work too hard, or because they consider their wages insufficient. The grave inconvenience of this not uncommon occurrence should be obviated by public remedial measures; for such paralysing of labor not only affects the masters and their work people alike, but is extremely injurious to trade and to the general interests of the public; moreover, on such occasions, violence and disorder are generally not far distant, and thus it frequently happens that the public peace is imperiled. The laws should forestall and prevent such troubles from arising; they should lend their influence and authority to the removal in good time of the causes which lead to conflicts between employers and employed.
Source: Rerum Novarum (Vatican.va)