"What then shall we say to these things? If God is for us, who can be[h] against us? He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things?" Romans 8v31-32
Christians often say that "God is good", when a day has gone well... but surely the reality is that, its not in our circumstances that we see God is good - but in the giving of Jesus for us. That is evidence and testimony enough!
(See Sinclair Ferguson, 4th September 2005 - The Heart of the Gospel)