The Gr. term (τὸ ξύλον, lit. [Note: literally, literature.] ‘the wood’) translation ‘stocks’ in Authorized Version and Revised Version is used to denote a wooden framework containing holes, in which the feet of criminals were confined. This ancient mode of punishment (cf. Job 13:27; Job 33:11) survived in lands further west till a comparatively recent period. Among both Greeks and Romans it was employed in the case of freeborn malefactors as well as slaves. When Paul and Silas were thrown into the inner dungeon of the prison at Philippi, the jailer, who was charged by the Roman magistrates (known as the Duumviri) to keep the prisoners safely, for greater security took the precaution of enclosing their feet in the stocks (Acts 16:24). This infliction was part of the shameful treatment endured at Philippi to which the Apostle afterwards referred in his First Epistle to the Thessalonians (1 Thessalonians 2:2).
W. S. Montgomery.