What does the voice of many waters mean in the book Revelations?

The Holy Spirit is like the LIVING WATER giving ETERNAL LIFE. 144,000 are the chosen ones who are given the Holy Spirit – they are marked with the seal of God. That’s how God sets them apart from the rest, to be holy. So they have the sound of living water within them because the Holy Spirit lives within them and speaks through them.

Revelation 14:1–2
“Then I saw the Lamb standing on Mount Zion, and with him were 144,000 who had his name and his Father’s name written on their foreheads. And I heard a sound from heaven like the roar of mighty ocean waves or the rolling of loud thunder. It was like the sound of many harpists playing together.”

Pool of Bethesda, John 5:4