It had been revealed to him by the Holy Spirit that he would not die before he had seen the Lord's Messiah. (NIV)
And it had been divinely revealed (communicated) to him by the Holy Spirit that he would not see death before he had seen the Lord's Christ (the Messiah, the Anointed One). (AMP)
And it was revealed unto him by the Holy Ghost, that he should not see death, before he had seen the Lord's Christ. (KJV)