Will a plea to return abducted children from Israel under the Hague Convention ever be heard in a rabbinical court in Israel?

No! Rabbinical courts in Israel have no jurisdiction to hear pleas for an order to return abducted children. Jurisdiction to return the children lies only within the civil system – i.e. at first instance with the Family Court, and then at the appeal stage with the District and Supreme Courts. A rabbinical court in Israel is, however, regarded as a judicial authority entitled to give a legal opinion or declaratory judgment about whether children were habitually resident in Israel or not prior to their removal/retention, and whether they abducted or not.
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