Revelation 15:5
And after that I looked, and, behold, the temple of the tabernacle of the testimony in heaven was opened:
Cross-reference
Revelation 11:19 also describes the heavenly temple being opened, revealing the ark of the covenant – the same scene.
Revelation 14:17 mentions an angel coming out of the heavenly temple – the same temple referenced here.
Revelation 16:1 describes a voice from the temple commanding the bowl judgments – the same heavenly temple now opened.
Revelation 16:17 says a voice from the temple declares 'It is done' – the same temple in heaven.
Exodus 25:21 describes the earthly 'tent of witness' with the mercy seat – the pattern for the heavenly sanctuary opened here.
Numbers 1:50 uses the same phrase 'tabernacle of the testimony' – the OT tent of witness prefiguring the heavenly one.
Numbers 1:53 similarly mentions the 'tabernacle of the testimony' – the earthly counterpart to the heavenly tent opened here.
Matthew 27:51 describes the tearing of the temple veil – opening access to the Holy of Holies, prefiguring the heavenly temple's opening.