Forty days had passed and the resurrected Christ had been right there before them proclaiming the Kingdom of God and all that He fulfilled in the law and the prophets! But they still did not get it. Their hearts may have burned when He was in front of them, but they still were not fully grasping things.
They merely saw Him as the leader of a physical revolution that fell far short of what the Father and Son actually had in mind—the real change God wanted was to turn the whole world upside down (Acts 17:6).