"As obedient children, do not conform to the evil desires you had when you lived in ignorance. But just as he who called you is holy, so be holy in all you do; for it is written: 'Be holy, because I am holy.'" NIV translation
We hear and even speak the word "holy" often but do we stop to remember its meaning? In Exodus and Leviticus, God called His people out of bondage and into freedom and a right relationship with Him. They were to be set apart by God and for God. The same is true of us today and that is what this passage is talking about. Just as the Israelites were called out and told to do some things while not doing others we are as well and that is what Peter is talking about in not conforming to our evil desires. He says that we did so when we were ignorant but we are no longer ignorant since we have been made new and have the Holy Spirit inside us. Have you personally got the Spirit? If you do, then you have the power to be holy.
"Since you call on a Father who judges each man's work impartially, live your lives as strangers here in reverent fear." NIV translation
We, as Christians, will be judged on the last day not for salvation but for rewards. In Revelation 20:12 & 13, we see different books opened and then the book of life was opened and we are told that each person was judged according to what they had done. We are secure in our salvation but what we do with it will affect our rewards in heaven.
"For you know that it was not with perishable things such as silver or gold that you were redeemed from the empty way of life handed down to you from our forefathers," NIV translation
We are all familiar with the phrase "been there, done that" well Peter is sorta saying that here. He reminds us that we were once in the world and experienced what it had to offer. He also reminds us that there was nothing else that could fill our lives and make us whole except for the relationship we now have with the Father through Jesus Christ. The final part of this verse should cause all of us who are parents to pause because it says that the empty way of life (life in the world instead of life in the Spirit) was handed down by "our forefathers". We, as Christian parents, have a huge responsibility to children and that is telling them about Jesus and walking in the power of the Holy Spirit instead of walking in the ways of the world. It has to be more than talk in our lives as the kids must see an example of walking in the Spirit from our lives.
"but with the precious blood of Christ, a lamb without blemish or defect." NIV translation
Peter reminds us that it was the shedding of Jesus' blood that redeemed us and that nothing else could do it. This refers back to the plague of the firstborn in Egypt and how God had the Israelites put the blood of the lamb on their doorposts so that the angel of death would pass over their homes and spare their firstborn sons. The blood had to come from their best lamb and that refers to the fact that Christ knew no sin and yet became sin to purchase us.