The goal of this essay is to reopen the unfortunately unrefined but still illuminating proposal of August Dell a century ago – a proposal to read the motif of ‘bind and unbind’ in Matt 16.19 against the backdrop of ancient magical conventions – and to corroborate this hypothesis with philological precision and contextualisation. The present study seeks to demonstrate how central the motif of ‘bind and unbind’ was to most binding spells and amulets, and how the verbs λύειν and δέειν and their cognates might have evoked the conventions of binding magic when heard in religious and ritual contexts. We see Matt 16.19 as a literary reappropriation of a typical binding spell, crafted to highlight Peter's authority to ‘bind’ and ‘break’ whatever entities he should choose. Jesus' guarantee that he/God will ‘unbind’ whatever target Peter ‘unties' is to be understood as a clear indication that Peter is endowed with an invincible potency over every other spiritual entity, symbolised by the power to break any ‘binding’ spell. The security of the church against malevolent and harmful spiritual entities is further guaranteed by Christ's promise, if read in ancient binding magical conventions: Christ will give Peter the key of the kingdom of heaven so that Peter as the key-bearer may become a figure who can channel the full potency of the keyed object.