Sorry but that's not true. Not every word that begins with re- means to do something again. Replenish means to fill up.

REPLENISH a: to fill or build up AGAIN <replenished his glass> b: to make good : replace

I was trying to keep it simple but...

According to Merriam-Webster:
Replenish- 1 archaic: to supply fully
2 to fill or build up again

Notice how the first one is archaic; the second one is more recent. The King James Bible was written in Old English.

But really to explain words of the Bible you need to find the meaning of the original Hebrew word(s):

(Qal) to be full a) fulness, abundance (participle) b) to be full, be accomplished, be ended

(Niphal) 1) to be filled, be armed, be satisfied 2) to be accomplished, be ended

(Piel) 1) to fill 2) to satisfy 3) to fulfil, accomplish, complete

(Pual) to be filled