is a result of God's grace, thus, never dare to take credit,

the other side
insists on
man says the final word YES or NO because he himself is capable
to decide.

I, myself, am a dead man and I am not capable to decide
whether believe in God or not unless God give me a new life,
yes, under His grace, He give me new life,
so
I became capable to believe in Him,
as a result and based on His promise,
I am saved forever!

In short: the difference from two sides:

God decided I would be saved
or
I decided I would be saved

who is the decider!

Salvation is a package including

100% What God do
plus
100% What I do