Sphragis-a signet; by implication the stamp impressed (as a mark of privacy, or genuineness) on a book or document or scroll :- a seal. Strong’s Talking Greek & Hebrew Dictionary.

In the first century, when Revelation was written, a person of authority would seal important documents to keep them secret or to authenticate them. Roman law required a Last Will and Testament to be sealed 7 times, as the wills of Caesar Augustus and Emperor Vespasian were. This scroll with 7 seals, appears to be a metaphor for the last will and testament of Jesus, the Messiah.

thysiastērion-from a derivative of <G2378> (thusia); a place of sacrifice, i.e. an altar (special or genitive, literal or figurative). Strong’s Talking Greek & Hebrew Dictionary.

Genesis 8:20 (KJV)
²⁰  And Noah builded an altar unto the LORD; and took of every clean beast, and of every clean bird, and offered burnt offerings on the altar.

Logos-from <G3004> (lego); something said (including the thought); also reasoning (the mental faculty or motive; by extension a computation; specifically, with the verses in John, the Divine Expression (i.e. Christ. Messiah in Hebrew) Strong’s Talking Greek & Hebrew Dictionary.

John 1:1-5 (reconsidered))
In the beginning (at the commencement of time) was the Word (the Logos). The Word (the Logos) was with (by the side of) God (Theos). The Word (the Logos) was God (Theos). The same (the Logos) was in the beginning (at the commencement of time) with God (Theos). All things came to be through the Logos and without the Logos nothing would have come to be that did come to be. In him (the Logos) was life (Zoe); and life (Zoe) was the light (manifestation; luminousness) of humanity. And the light (manifestation; luminousness) shined (appeared) in darkness (obscurity; dimness); and the darkness (obscurity; dimness) comprehends (possesses) him (the Logos) not.

John 1:14 (reconsidered)
And the Word (the Logos) came to be generated into flesh (a human body), and to reside with us, so we could look closely at his glory, the glory of the only-born son of the Father, complete graciousness and truthfulness.

Jeremiah 2:13 (KJV)
My nation commits two evils; relinquishing the fountain (source) of living water, and chiseling cisterns, broken cisterns, holding in waste water.

John 4:9-14 (reconsidered)
A Samaritan woman said Jesus, “How is it that you, being of Judea, ask a drink from me, when I am a woman from Samaria? The Judeans have no dealings with Samarites. Jesus responded to her by saying, “Whether you are aware of the gift of God, or who he is speaking to you, ‘Give me a drink!’ You and whomever asks me, as many as ask me, I give them living water.
The woman said to him, “Sir, you have nothing to draw water with, and the well is deep, from where then do you have living water? Are you greater than our father Jacob, who gave us this well, that we drink of and that he himself, his children, and his cattle drank of? Jesus responded to her saying, “Whosoever drinks this water shall thirst again but whosoever drinks the water that I shall give him, he will never thirst again. The water that I shall give him, will be in him, a well of water springing up into everlasting life.”

John 7:37-42 (reconsidered)

On the last day of the Great Feast, Jesus stood up and cried out saying, “If any man thirsts, let him come to me, and drink. Believe in me continually, as scripture says, ‘from his belly (matrix; womb) flows a river of living water.'” (For this thing spoken of is the Spirit, which believers in him will receive. For the Holy Spirit wasn’t yet given because Jesus was not yet glorified.)

pleroo-from <G4134> (pleres); to make replete, i.e. (literal) to cram, level up, or (figurative) to furnish (or imbue, diffuse, influence), satisfy, finish (a period or task), verify (or coincide with a prediction), accomplish, (be) complete, end, expire, fill (up), fulfil, (be, make) full (come), fully preach, perfect, supply. Strong’s Talking Greek & Hebrew Dictionary.