But what is this "gospel" to be learned and preached?
A "gospel" in Roman times was the proclamation that a new "Savior of Mankind" had just ascended the Imperial throne. For early Christians, then, it meant the analogous proclamation that Jesus was God's chosen ruler of the Earth--and thus it became a term for books about Jesus. But the name "Jesus" belonged to a multitude of First Century Jews, and has since been applied to a multitude of false images, each captive to one ideology or another.
The real Jesus is veiled, his life and nature subject to dispute. As far as I can tell, modern Friends think that sitting quietly for an hour each week shows us everything we need to know of the Christ spirit, who "enlightens everyone who comes into the world"--and hence the solution to the Jesus puzzle is not on the test.
True, we weren't given this problem to trip us up, or so we could earn a heavenly 'A' with 'the right answer.' If 'right answers' were the object, we would have had authoritative writings of Jesus to misunderstand. Nothing of the sort was left us, because the kind of answers we need require a passionate desire for understanding, plus reliance on God to bring us to it.
The gospels confront us with God's anointed king of Israel--rejected, despised and feared by all authorities, civil or religious--misunderstood and abandoned even by his own followers. This man is a long way from anything we can understand as "success." This, they say, is the man God raised from death, to sit at his right hand. This is the spirit who secretly rules the world, in the midst of all apparent darkness. But can we make anyone believe it; should we strain to believe it ourselves? So far as we don't know, we are just offering another notion.
To my mind, the "good news" is that the Spirit within us is the Creator of the world, a being of ultimate goodness and ultimate power.
But no particular proposition is "the power of God to salvation." God's actual power and will to save us, that itself is what delivers us from one trouble to the next. And how can we think to convey God's divine power?
We can tell people about it, in hopes they won't go on suffering from false fears and wasting their strength chasing false remedies.
A child at sea in a storm, not expecting rescue, can do many foolish things hoping to save himself. He might put up a sail, row in circles or random directions, try to anchor in bottomless ocean. He might even jump overboard and swim. But once he knows a rescuer is coming, he can cooperate: turn into the wind, stay in place as best he can, wait to be found. This is what makes true beliefs important. And that is the value of preaching, little as we love it. "How could [people] invoke one in whom they had no faith? And how could they have faith in one they had never heard of? And how hear without someone to spread the news?" [Romans 10.14]
Preaching, in our own power, won't do it. No-one's belief is under our control, not even our own. Convincing anyone to rely on God, that's a job for God's power itself. God is what we need to rely on, and God is, fortunately, all we can rely on.
We do need to learn how.
We were born into a faithless time, and so it isn't easy. But that is what the state of the world demands. We just might need to take it slowly, as God has taken so very long bringing us through our lives this far. Who could expect comfortable people or urgently concerned people to make great leaps of faith?
We can start by asking God for hints in small matters, expecting to be answered not by a Heavenly Voice but by whatever comes to us, whether in our own minds or in the outside world. Don't, if you can help it, despise these hints, or calculate their odds, or reduce them to "coincidence" in your mind. Trust in the one who teaches us. Many of us can say, from our own experience, that this works.