1 Peter 2:1 - 3

"Therefore, rid yourselves of all malice and all deceit, hypocrisy, envy, and slander of every kind. Like newborn babies, crave pure spiritual milk, so that by it you may grow up in your salvation, now that you have tasted that the Lord is good." NIV translation

Peter starts us off here by telling us to remember what we learned in the 
first chapterWe are to remember that because we have the hope that we studied in that chapter, we are to get rid of the sin in our lives. We are also reminded from the last chapter that we are given the power to overcome our flesh through the gift of the Holy Spirit. 
He also tells us to crave pure spiritual food which means not only get rid of the bad but to replace it with the good things which come from God. We also have the promise that, when we do that, we will "grow up" in our salvation. The more you obey God the easier it will get to listen and follow Him.

1 Peter 2:4 & 5

"As you come to him, the living Stone-rejected by men but chosen by God and precious to him- you also, like living stones, are being built into a spiritual house to be a holy priesthood, offering spiritual sacrifices acceptable to God through Jesus Christ." NIV translation

This passage speaks of the transformation of worship from a building to a daily walk. The temple was made out of stone and many stones were stacked on top of each other to create the walls. Here, we see that we are a spiritual house of worship to God. When we were given the gift of the Holy Spirit, we became a house of God and He dwells within us every day.

 Unlike the Temple, we do not need priests to go to God on our behalf as we have God living in us as the temple. In the old Temple, animal sacrifices were offered as the temporary payment for sin but, through Jesus Christ, our sins are paid for forever. We no longer have to offer sacrifices to be saved but instead we offer spiritual sacrifices which are acceptable to God because of Jesus. These spiritual sacrifices can be simply putting God first in our lives and that means listening to him and doing what He asks of you.