Perceiving,metabolizing and applying bible doctrine is key to the works that a Christian is to do.
Acts 16:31 is salvation for any man.It can not be lost and it cannot be attained any other way.
You're right about Acts 16:31
But can it be that easy?
The Gospel of John, chapter 6
25 they said to Him, “Rabbi, when did You come here?”
26 Jesus answered them and said, “Most assuredly, I say to you, you seek Me, not because you saw the signs, but because you ate of the loaves and were filled. Do not labor for the food which perishes, but for the food which endures to everlasting life, which the Son of Man will give you, because God the Father has set His seal on Him.”
28 Then they said to Him, “What shall we do, that we may work the works of God?”
29 Jesus answered and said to them, “This is the work of God, that you believe in Him whom He sent.”
30 Therefore they said to Him, “What sign will You perform then, that we may see it and believe You? What work will You do? Our fathers ate the manna in the desert; as it is written, ‘He gave them bread from heaven to eat.’”
32 Then Jesus said to them, “Most assuredly, I say to you, Moses did not give you the bread from heaven, but My Father gives you the true bread from heaven. For the bread of God is He who comes down from heaven and gives life to the world.”
34 Then they said to Him, “Lord, give us this bread always.”
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Jesus said,
"This is the work of God..."
and continued to explain the plan of God: "That you believe in Him whom He sent."
Notice that Jesus replied to their pride in their ancestors who had personally been given the mana from heaven. God had instructed them to save that mana in the arc of the covenant as a remembrance. They did remember. And took great pride in their heritage. But the Lord set them right about what had happened 'behind the scenes' -- God humbled their ancestors and allowed them to become hungry that He might then feed them. Somewhere along the line they had lost track of the "why" of it all and had again lifted themselves. In another place, Jesus admonished, "Beware the leaven of the Pharisees..."
Jesus had just fed them with the loaves and fishes. They tried to lift themselves declaring, "
Our fathers were fed with the mana from heaven..."
Then asked, "What are the works of God?" They wanted to do the miraculous. "
What shall we do, that we may work the works of God?" Their dreams were of very grand things.
Jesus, the true mana, replied, "Believe in Him whom God has sent."
We see later that Thomas believed and declared, "My Lord and my God..." (John 20:28-29) Compare John 6:35, 36 with what Jesus told Thomas. Jesus was talking about us. We are those who have not seen.
Jesus was speaking to those who had just been fed by the loaves and fishes: John 6:36 (NIV):
"But I said to you that you have seen Me and yet do not believe."
Jesus speaking to Thomas: Jesus said to him
, "Because you have seen Me, have you believed? Blessed are they who did not see, and yet believed." (John 20:29)
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Now we read again the quote that gr8grace3 brought: Acts 16:30-31
...
"Sirs, what must I do to be saved?"
They said, "Believe in the Lord Jesus, and you will be saved, you and your household."