This 3^rd Sunday of Advent is traditionally known as Gaudete Sunday (Rejoice) Latin translation of Phil 4:4-5. The first, second readings and the Psalm all speak of joy, gladness and praise. 
“Shout for joy, O daughter Zion! Sing joyfully, O Israel…Be glad and exult with all your heart, the Lord …has turned away your enemies. The king of Israel, the LORD is in your midst, you have no further misfortune to fear,…fear not, O Zion, be not discouraged… The LORD, your God, is in your midst, a mighty Savior; He will sing joyfully because of you...” 
The Psalm has very much the same tone. It’s described as the song of thanksgiving:
“God indeed is my savior, I am confident and unafraid. My strength and my courage is the LORD. With joy you will draw water…Give thanks to the Lord…Sing praise to the LORD for his glorious achievement;…”
 
St. Paul concludes the call to us to rejoice today. 
“Rejoice in the LORD always. I shall say it again; Rejoice! Your kindness should be known to all. The LORD is near have no anxiety at all, but in everything, by prayer and petition, with thanksgiving, make your request known to God. Then the peace of God that surpasses all understanding will guard your hearts and minds in Christ Jesus.” Very inspiring text for prayer and meditation during this Advent and indeed all the time.
 
In the gospel we hear from the great Advent figure, John the Baptist, preaching the gospel of social justice. To the crowds he said, “Whoever has two cloaks should share with the person who has none.” Advent is a season of charity, of reaching out to those who are hungry, thirsty, homeless and naked.
To the tax collectors he said, “stop collecting more than what is prescribed.” To the soldiers he said, “Do not practice extortion, do not falsely accuse anyone, and be satisfied with your wages.” In a nutshell, John is saying, wherever you are working that’s fine but, do your work in love, mercy, transparency. Be a good servant or steward, trustworthy and sincere. No to corruption, cheating or stealing knowing that you are a Christian, a disciple and ambassador, a representative of the LORD.
ALWAYS remember your identity and mission. John the Baptist knew his identity, one sent to baptize with water, his mission being to prepare the hearts of the people for the LORD who will come and baptize with the Holy Spirit and fire.