Exodus 28:28

And they shall bind the breastplate by the rings thereof
By the rings at the lower ends of it, as it was by the rings at the upper ends of it to the shoulder pieces of the ephod; or "lift it up", so some interpret it ^F23 as if it was said, they shall lift up the breastplate to join it with the ephod that is above it:

unto the rings of the ephod with a lace of blue;
this blue lace was put both into the rings of the breastplate and into the rings of the ephod, and so being tied in a knot, fastened them together, as the shoulder pieces of the ephod and the breastplate were coupled above, with wreathen chains of gold put into rings: now this was done,

that it may be above the curious girdle of the ephod:
that the breastplate might be above it, or else the lace of blue:

and that the breastplate be not loosed from the ephod:
but be kept tight and close to it by the wreathen chains above, and by the knots of blue lace below; which may denote the conjunction of the prophetic and priestly offices in Christ; the former being signified by the breastplate of judgment, in which the Urim and Thummim were, and the latter by the ephod; or else the union of the saints to Christ, the bond of which is everlasting love, from which there can be no separation; this union can never be dissolved, his people can never be loosed from him, they are members of his body, and one spirit with him.