Summary: To prove in the bible that GOD's WORK is that all men must believe in JESUS, the only One that can save us.
There is one belief in the bible that made GOD work for our entire and complete salvation. That is to believe in JESUS - the One GOD had sent. (John 6:29)
There are other three beliefs we can see that GOD did not credited for our salvation as seen in this passage. Belief in perishable food, we believe we are the provider to our family as a father and we provide the best food for them but we forgot the Only Way to Life is the Bread of Life - JESUS and to eat His WORDS. (John 6:48, John 14:6, Matthew 4:4)
Another discredit belief by GOD is the belief in your own good works or self (John 6:28). We believe whatever good works we do in this life earns us heaven as if our good works obligated GOD to write our name in the Lamb's book of Life. (Revelations 20:15), well we're sincerely wrong if we believe that. Someone said to me that he believes that there is inherent goodness in every man but the Bible said "all have sinned and fall short of the glory of GOD." (Romans 3:23, Romans 6:23) so how about that? It seems like the so-called "inherent goodness" is really inherent sin or the Adamic sinful nature that is. Teaching your children early in life to "do good to get to heaven" will earn them a rightful place in hell. (Ephesians 2:8-9, Isaiah 64:6)
A third discredited belief by GOD is a belief in the miraculous signs or in miracles (John 6:30). Yes, belief in JESUS will work miracles in your own life, I believe that. What I'm saying but belief in miracles alone to lead you to believe in GOD or CHRIST is the One that is discredited by GOD. I used to believe before when I was still an unbeliever is I need to be exposed to signs, miracles and wonders to give me faith in GOD which brought more disbelief in me. The solution is you come to CHRIST or GOD believing in Him already. (Hebrew 11:1, Hebrews 11:6, 1 Corinthians 14:22)
The last belief that is the one credited by GOD is to believe in the SON of GOD. This is the work of GOD that you believe in JESUS. (John 6:29) There's no other name or saint's name that can save you - only JESUS can. (Acts 4:12, Philippians 2:9-11, John 14:6)
Do you believe in JESUS?
If YOU DO, THEN acknowledge CHRIST before GOD and men, because GOD is the One that worked in you.