{An evil and adulterous generation} (genea pon(8872)a kai
moichalis). They had broken the marriage tie which bound them to
Jehovah (Plummer). See  Ps 73:27  Isa 57:3ff.  62:5  Eze 23:27  Jas 4:4  Re 2:20 . What is "the sign of Jonah?"