Jesus | The Lamb of God
Easter is upon us, and Easter ushers in thoughts of its meaning, namely Jesus' passion. Let's set the scene for the story by identifying our state. Romans 6:23 says, "For the wages of sin is death but the free gift of God is eternal life in Christ Jesus our Lord." This death-penalty for sin comes from the Garden of Eden (Gen. 2:17) and is inherited by all mankind via what is called original sin (Rom. 5:12). It can be seen based on the structure of the verse that since death is paralleled to life (see diagram below) the death referred to is an eternal death.
The wages that are received are like any other wages: earned, deserved, and "what you have coming." This is a similar idea to earning a wage at a job, you've got your paycheck coming. In this case, however, what you did to earn the wages was sin. Sin is, or results from, an inward preference for anything above God (Romans 1:22-23,3:23). Sin is an exchanging of God for lesser things. This is why eternal death is necessary because God, infinite and all satisfying God, has be traded for things which are lesser and could never satisfy (Jeremiah 2:12-13). The Bible says we should be shocked and appalled that such a horror would happen.
But, thankfully the verse does not end there. God has a free gift (unearned, undeserved, something you don't have coming) which is paralleled to the wages (see diagram above). That free gift may only be bestowed by God and is not earned. As much as we receive the wages because of sin, so we receive the free gift because of God alone (Romans 5:8; 1 John 4:10). The gift is Himself in the person of Jesus whom we get to spend eternity with, beholding His glory(John 17:24; Revelation 5:9-10,12).
Surely at this point you're asking yourself, "How do I exchange the wages, that I rightly deserve, for this free gift, which I could never earn?" The answer to that question (and there is an answer) is worth spending your life and energy to find. It is good to note here that you must answer the question for yourself. Not answering the question is accepting the wages you've earned...
The original answer to this question was to kill a lamb, and its blood would be a sign that God would pass over His people (Passover) and not kill them (Exodus 12:5-13). This answer was a picture of the true and perfect answer, who is Jesus Christ -- the Lamb of God. Consider the quoted commentaries here in comparison between Jesus' passion and the Passover lamb's passion, some meditation, and then application.