1 Kings 11:42
And the time that Solomon reigned in Jerusalem over all Israel was forty years.
Cross-reference
1 Kings 11:4
Historical context
1 Kings 11:4 reveals Solomon's apostasy in old age during the same 40-year reign — explaining the kingdom's division.
1 Kings 2:11
Parallel
1 Kings 2:11 records David's 40-year reign, mirroring Solomon's 40-year reign here — a parallel in royal summaries.
2 Chronicles 9:30
Parallel
2 Chronicles 9:30 states the same 40-year reign verbatim — a direct parallel account.