The difference between the two is scenario is that,
a. God was trying to bring to David’s consciousness that He is a God of principle and does not joke with whatever He says.
b. When your heart is sincere and pure towards Him, even if people meant evil for you, God will go to every length to defend you.
c. When you obey authority, God will honour you. The king has spoken, Obed-Edom did not argue, and God honoured him. Even when it was the people that made the choice earlier, in the case of Abinadab, God still honoured Abinadab. I Samuel 7:1, I Chronicles 13: 13