Exodus 39:18 describes chains and settings attached to the ephod from verse 2, completing its construction.

Exodus 25:7 lists stones for the ephod — the same ephod being made here with materials specified earlier.

Exodus 28:6-12 gives detailed instructions for making the ephod — Exodus 39:2 executes those instructions.

Exodus 28:2 commands making holy garments for glory and beauty; this verse begins the ephod, fulfilling that command.

Exodus 28:4 lists the ephod among the garments to be made; here its construction starts.

Exodus 28:5 instructs receiving gold and colored yarns; this verse uses those exact materials for the ephod.

Leviticus 8:7 describes putting the ephod on Aaron — the ephod made in Exodus 39 is now used in consecration.