“For the earth will be filled…”
‘filled’ implies completely full

“…with the knowledge…”
the Greek word here ‘gnosis’ means to know intimately – similar to a husband and a wife who know each other’s nakedness, annoying habits, body odour, deepest secrets etc. Only with God, it’s even deeper than that – to truly know inside and out

“…of the glory of the Lord…”
his glory is his grace, his love, his peace, his creative beauty, his joy, his abundant life, his forgiveness, his goodness

“…as the waters cover the sea”
all incorporating, saturating, satiating

I want to ‘know’ you Jesus and I look forward to the day when the whole earth is full of your glory and every soul ‘knows’ you