We tend to follow pretty rational processes for weighing the worth of promises. They work rather well in the real world of normal life. Expectations are predictable, and reason and logic run the merit of the promise. That is, except when God and faith enter the picture.
For Abram - soon to become Abraham - God's announced covenant throws the old guy to the ground in a fit of uncontrolled laughter. (You remember the story of Sarah's guffaw when the visitors come. Abraham laughed first, and it wasn't a snicker.) Of course, the covenant includes Abraham and Sarah having a child, even though they've been collecting social security for a decade or two.
Abraham seeks to have God's blessing on Ishmael, dismissing God's promise as a joke of some sort. But God insists that Ishmael will have his legacy, but Abraham and Sarah will have a child. Some promise alignment was in order since the misalignment was quite evident.
In Mark, Peter had just scored big points for having correctly name Jesus as "The Messiah" when Jesus asked, "Who do people say that I am? Who do you say that I am?" However, Jesus has more to teach.
Jesus begins teaching about what he expects to happen, the pain, suffering, and persecution, the arrest, execution, and resurrection. This doesn't square with Peter's understanding of "Messiah" at all. Jesus seems disturbingly negative, so Peter asserts himself and pulls Jesus to one side to give him some pointers on what being a Messiah means.
Jesus realizes that Peter had misread things terribly - a promise misalighnment. Jesus shuts him down by declaring "Get behind me, Satan!" and citing the disparity between God's way and the world's way which Peter has been deluded into believing.
As a crowd-pleaser, Jesus had much to learn as he continues his very difficult teaching. Continue this exploration with the sermon video below, noting the downloads below the video panel.