"When Israel, standing on the banks of the Red Sea, looked back and saw their old masters dead upon the shore, their hearts thrilled with joy and the sands of the desert vibrated and re-vibrated as Moses led in the song of victory and deliverance. The allusion here is to the Israelites of old who, after having passed through the Red Sea dry shod, thus securing perfect and blessed deliverance from the bestial system of Egypt, stood upon the shore singing the song of Moses, Miriam and the women playing their tumbrels, while their enemies with their chariots and their chosen captains perished in the waters (Exodus 15)."

"Here is another sea — a sea of glass and fire. Here is another company, standing on another shore, that has won the victory over its enemies. Who might this company be? What might be the sea upon whose shore they sing the song of triumph and praise to their Lord and Deliverer? Methinks I have stood upon that very shore. As surely as the raging sea bespeaks multitudes of surging, clamoring, restless, sinning humanity, so does the exquisite sea of glass represent an assembled throng of transformed saints in whose hearts the spirit of the Lamb rules. This great sea of the sons of God is calm, serene, tranquil, and quiet — the bestial nature has been dealt with and these abide in the peace, joy, righteousness, and power of the kingdom of God. Ah, yes, I have stood upon that shore, yea, and do stand with an innumerable company of men and women whose faces are set and whose hearts are fixed to do only and completely the will of the Father. These are they who live and walk in the Spirit, the firstborn-destined who are being delivered from the power of the beast. The glassy sea is here mingled with fire — the fiery trials and processings by which the Father purifies His sons, sharpening their vision, whetting the appetite for things eternal and heavenly, slackening the desire for all that is earthly and worldly."

Much more in the link:

https://www.godfire.net/eby/rev176.html