I'd bet Leviticus isn't in your top five favorite books of the Bible. It's full of regulations and messy, bloody rituals. But even though the practices of this book no longer have any bearing on us under the new covenant, its principles are still applicable—including those we find in the ordination service of Aaron and his sons, the first priests of Israel.
In Leviticus 8, we read that "[Moses] brought...the ram of consecration. Then Aaron and his sons laid their hands on the head of the ram, and Moses killed it. Also he took some of its blood and put it on the tip of Aaron's right ear, on the thumb of his right hand, and on the big toe of his right foot" (vv. 22-23). Then he did the same with Aaron's sons (see v. 24).
Pretty strange, right? Well, the symbolism runs deeper than that: the right side of a person was considered their dominant or best side. So in singling out the right ear, hand, and foot, Moses was essentially saying, "I'm consecrating you to hear God's word, do God's work, and walk in God's ways." The equivalent of this principle in the New Testament is found in Romans 12:1: "Present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service."
Have you ever thought of the potential of a single human body dedicated wholly to the purpose and glory of God? Scripture is filled with stories of the Lord using different members of people's bodies. Take Moses' mouth, for example. He stuttered, but God said, "I'm going to empower you to speak words before Pharaoh and speak My love to Israel." Moses' mouth by itself was not impressive, but that same mouth dedicated and surrendered to God was very impressive.
What about David's hands? Give a sling to that kid and he was a dead-on marksman for Goliath's forehead. And then there are Paul's feet. Over three missionary journeys, he brought the gospel from Jerusalem all the way to Rome (see Isaiah 52:7).
Now think of your life as the base of operations for God. The Bible says that "your body is the temple of the Holy Spirit" (1 Corinthians 6:19). Think of what God could do through you if you woke up every day and said, "Lord, here's my mouth, here are my feet, here are my hands—go for it."
Just like with Aaron and his sons, God wants to use you in this way. He doesn't just use preachers or people He calls into official ministry. If you are part of the priesthood of believers (see 1 Peter 2:9-10), you are in the ministry. Find out specifically what He has put before you to do, then use your body for His glory.
God doesn't have to use us to get His work done in the world. In fact, He would be better off if He didn't use us. So why does He? He likes to use the foolish things of this world (see 1 Corinthians 1:27) so that people see His work and say, "God is so powerful and good." What an incredible privilege it is that He's pleased to work through such weak instruments as you and me for His glory.