It seems that sèvi by itself means serve. Like "Nap sèvi Bondye." But sèvi ak means use. Like "Pa sèvi ak bik sa." Is that correct? Do you have to use ak to make sèvi mean use? Also how would you translate sèvi in this verse: "Mwen menm, mwen sèten m'a viv pou m' wè jan Bondye sèvi byen ak pèp li a."

Yes.
Sèvi - to serve, to worship, to serve as
egzanp:

1. N'ap sèvi Bondye.
    We worship God.
or
2. Ou pa ka sèvi de Bondye alafwa.
    You can't serve two masters at once.

sèvi or sèvi kòm or sèvi pou - to serve as, to use as

3.  Li pran m sèvi bòn li.
     He used me as his maid.

4.  Mwen pa t janm di sa.  Ou kapab sèvi m temwen.
     I never said that.  You can serve as my witness.

5. Li pran chemiz nèf mwen sèvi tòchon.
    Li pran chemiz nèf mwen sèvi kòm tòchon.
    He took my new shirt and used it as rag.

sèvi ak - to use, to make use of, to have to do with
egzanp:
6. Nou pa sèvi ak kiyè nan kay sa a.
   We do not use spoons in this house.

in your example:
sèvi byen ak → to treat well

7. "Mwen menm, mwen sèten m'a viv pou m wè jan Bondye sèvi byen ak pèp li a."
   "As for me, I'm sure I'll live to see how God treat his people well.:

other similar examples:

8. Li sèvi byen ak mwen.
   He treated me well.

9. Mwen va toujou gen madan Janot rekonesans.  Lè pitit mwen yo te rete lakay li, li te sèvi byen ak yo.
   I'll always be grateful to Mrs Janot.  When my kids stayed over at her house, she treated them well.


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