Mk 11:7-11, Jn 12:13, 1 Jn 1:3-4, Lk 2:10-11
In the Old Testament, when King David moved the ark of God from the house of Obed-edom to the City of David, the people of Israel were filled with joy. (2 Samuel 6:12-15)
2 Samuel 6:12 And it was told king David, saying, The Lord hath blessed the house of Obededom, and all that pertaineth unto him, because of the ark of God. So David went and brought up the ark of God from the house of Obededom into the city of David with gladness. 13 And it was so, that when they that bare the ark of the Lord had gone six paces, he sacrificed oxen and fatlings. 14 And David danced before the Lord with all his might; and David was girded with a linen ephod. 15 So David and all the house of Israel brought up the ark of the Lord with shouting, and with the sound of the trumpet.
When Jesus rode into Jerusalem on the colt, many Israelites were filled with joy. (Mark 11:7-11, John 12:13)
Mark 11:7 And they brought the colt to Jesus, and cast their garments on him; and he sat upon him. 8 And many spread their garments in the way: and others cut down branches off the trees, and strawed them in the way. 9 And they that went before, and they that followed, cried, saying, Hosanna; Blessed is he that cometh in the name of the Lord: 10 Blessed be the kingdom of our father David, that cometh in the name of the Lord: Hosanna in the highest. 11 And Jesus entered into Jerusalem, and into the temple: and when he had looked round about upon all things, and now the eventide was come, he went out unto Bethany with the twelve.
John 12:13 Took branches of palm trees, and went forth to meet him, and cried, Hosanna: Blessed is the King of Israel that cometh in the name of the Lord.
Christ, foretold in the Old Testament, has come. That Christ is Jesus. When we believe that Jesus is the Christ, we are filled with joy. (Luke 2:10-11, 1 John 1:3-4)
Luke 2:10 And the angel said unto them, Fear not: for, behold, I bring you good tidings of great joy, which shall be to all people. 11 For unto you is born this day in the city of David a Saviour, which is Christ the Lord.
1 John 1:3 That which we have seen and heard declare we unto you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son Jesus Christ. 4 And these things write we unto you, that your joy may be full.