Well Jesus was buried how is that "good news" (gospel)?
First, our Apostle Paul says the burial of Jesus is part of what the Holy Spirit means by
"gospel", in 1 Corinthians 15. The burial of Jesus is an event, not only news, by the way.
Jesus died for our sins; this is good for us. Jesus was buried >
I think of
"buried with Him through baptism into death" > in Romans 6:4.
So, I can see that His burial is somehow good for us.
"Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death? Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life." (Romans 6:4)
So, I now see in this, how the gospel is not only news, but it is
"in which you stand" (in 1 Corinthians 15:1). I think this means the death and burial and resurrection of Jesus ministers God's grace to us so we stand in the gospel in the grace which had Jesus so loving us while dying for us, and being buried, and then raised from the dead.
We are told to live this, including to live how Jesus was loving, on the cross >
"And walk in love, as Christ also has loved us and given Himself for us, an offering and a sacrifice to God for a sweet-smelling aroma." (Ephesians 5:2)
So, the real gospel is also our example.
Now I think of this > the Law of Moses could not do what Jesus of the gospel has done, by His death and burial and resurrection. The gospel is about all that God is able to do, which the Law of Moses can not do. Romans 8:3 says >
"For what the law could not do, in that it was weak through the flesh, God did by sending His Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh." (Romans 8:3)
And now I think of how John the Baptist called Jesus
"The Lamb of God who takes away the sin of the world!" (in John 1:29)
Through this, I see how Jesus does not only take away certain sins, but
"the sin" which makes us able to sin. This is good, and it seems Paul is saying the burial of Jesus is somehow included in the process of this. I consider it could mean Jesus in the grave was ministering grace, somehow, for us now . . . so we stand in His burial by standing in the grace of how Jesus was while buried. We are blessed through it all, how the Law of Moses could not do.
But there is the law of God which makes people
"free from the law of sin and death" >
"the law of the Spirit of life in Christ Jesus" > in Romans 8:2. This
"law" does what the Law of Moses
"could not do" (Romans 8:3).
So, in my opinion, the New Testament good news is the death and burial and resurrection of Jesus. And the grace of this is our benefit.