At the beginning of Jeremiah 40 we see the Babylonian commander acknowledge that God had given the Babylonians victory - and yet he did know God personally. People can recognize that God exists, and even that He does miracles, but they may refuse to accept Him as their Lord and Saviour. Being a believer is much more than head knowledge - after all, the demons know that Jesus is God, and Satan is well-versed in the scriptures. Knowing God is more than knowing about Him, we need to know Him personally, love Him, and follow Him.
In 40:4 Jeremiah was given a tempting offer - he was free to go anywhere. Going to Babylon He would have been favoured by the Babylonians but likely hates by the Judean exiles. Staying in Judah he would continue to experience hardship, but the Judeans would know he was not a traitor. Even though he could've chosen the easy route, he chose to stay. A challenge to us to choose the right way over the easy way.
In our NT passage we see that Jesus also chose the hard way - he did not take gall to help deaden the pain but chose to suffer fully conscious and with a clear mind. And, above all, He chose to lay down His life for us.
In Matthew 27:45 we see nature testifying to the gravity of Jesus' death as darkness fell over the earth. The darkness was both physical and spiritual.
In 27:46 we see the reason for Jesus dread as He prayed in the Garden. Of course the physical agony was horrible, but what was even worse was His having to take on sin and experience the wrath of God and separation from His presence. He experienced this for us so that we would never have to experience eternal separation from God.
Tomorrow's Bible In a Year Passage passage: Jeremiah 43-45; Matthew 27:51-66