The sacrifice of praise is the sacrifice God wants our "holy priesthood" to offer! How do we do that? With our mouths, by making a joyful noise to the Lord, speaking forth His praises, telling forth and extolling God's goodness.
 

First Peter 2:1 says:

ThWherefore, laying aside all malice, all deceit, hypocrisy, envy, and all evil speaking,

You cannot praise the Lord and speak evil at the same time. Jesus said you cannot get sweet water and bitter water out of the same fountain. You cannot have evil speaking and praise for the Lord coming out of your mouth at the same time.

The Apostle Paul said that there is nothing unclean of itself (Romans 14:14). He was speaking about ceremonial uncleanness in reference to the Jew. Under the Old Covenant, there were certain animals that were classified as clean and unclean. Unclean animals were never to be used in sacrifices to Jehovah God. It was not that the animals were dirty, it was just a distinction that God made between certain animals. But Paul said there is nothing unclean of itself, except to that man who thinks it is unclean. All things are made by God and they are to be received with thanksgiving. Let's go back to First Peter, and cover some other things concerning who we are in Christ Jesus.

First Peter 2:6-9:

6 TWherefore it is also contained in the Scripture, "Behold, I lay in Zion a chief cornerstone, elect, precious, and he who believes on Him will by no means be put to shame."

7 Therefore, to you who believe, He is precious; but to those who are disobedient, "The stone which the builders rejected has become the chief cornerstone,"

8 and "A stone of stumbling and a rock of offense." They stumble, being disobedient to the word, to which they also were appointed.

9 But you are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light;

This is why we shout, this is why we clap our hands, because we have been called out of darkness into His light. Many of us, before we were born again, walked in darkness for many years. There wasn't anything to shout about in the dark. But, praise God, we are in the light now, and there is a whole lot to shout about, because we are getting to see all the things we could not see when we were in the dark.

First Peter 2:10:

WhOnce were not a people but are now the people of God, who had not obtained mercy but now have obtained mercy.

There is a two-fold priesthood we are involved in under the New Covenant. First of all, we are a holy priesthood. The holy priesthood offers up spiritual sacrifices and praises. In other words, we extol and tell about the goodness of God. We praise His name, and we give Him honor and glory in verbal ways. Now the royal priesthood, on the other hand, deals with the things concerning God by His Word.

The holy priesthood function is our personal, private extolling and exalting of the Lord. We can also do that publicly, but it is primarily for our personal and private worship. In our royal priesthood function, we extol and present the things of God and the things of Christ through the Word of God--it is the manifestation that comes through the Word.