Thrust them into the inner prison - Into the most retired and secure part of the prison. The cells in the interior of the prison would be regarded as more safe, being doubtless more protected, and the difficulty of escape would be greater.
And made their feet fast in the stocks - Greek: and made their feet secure to wood. The word “stocks,” with us, denotes a machine made of two pieces of timber between which the feet of criminals are placed, and in which they are thus made secure. The account here does not imply necessarily that they were secured precisely in this way, but that they were fastened or secured by the feet, probably by cords, to a piece or beam of wood, so that they could not escape. It is probable that the legs of the prisoners were bound to large pieces of wood which not only encumbered them, but which were so placed as to extend their feet to a considerable distance. In this condition it might be necessary for them to lie on their backs; and if this, as is probable, was on the cold ground, after their severe scourging, their sufferings must have been very great. Yet in the midst of this they sang praises to God.