2 Chronicles 3:3

Now these are the things wherein Solomon was instructed for the building of the house of God. The length by cubits after the first measure was threescore cubits, and the breadth twenty cubits.

Cross-reference

1 Kings 6:2 gives the same length and width (60x20 cubits) for Solomon's temple, confirming the dimensions here.

1 Chronicles 28:11-19 details David's plans and dimensions for the temple, which Solomon followed in building.

1 Kings 6:3 describes the porch dimensions (20x10 cubits) adjacent to the house, complementing the house measurements here.