Because of sin (breaking God’s Law), we all will die. After we die on this earth, there is something called a second death which involves being cast into hell forever. Since God is holy and perfect and cannot have sin in His presense, He must punish sinners (lawbreakers). Yet this is not God’s desire. Because of His lovingkindness, He has provided a way of escape. He came to earth and paid the penalty Himself for breaking His holy perfect law (The Ten Commandents)! God through Jesus Christ was manifest in the flesh and died a brutal death on a cross (see Isaiah 53). When you repent from your sin and turn your life to Jesus Christ you will not enter the second death. As Jesus was telling Martha, it is only through Him that anyone can be saved from the wrath to come and live forever.
In the old testament of the Bible it was necessary (as a requirement of the Mosaic law that thousands of lambs were to be slaughtered and their blood shed to atone for the people sins. And yet their sins could not be completely taken away. There needed to be a perfect, holy and sinless offering. Thankfully now, lambs no longer need to be slaugtered each day because Jesus as God manifest in the flesh has become the final Lamb of God. He paid the ultimate penalty for our sins as the complete, holy and perfect sacrifice for us breaking His laws (The Ten Commandments).