The Bible is filled with instructions for when and how to worship.
On a daily basis: Ac 2:46-47; Ex 29:38-43; Ps 141:2; Eze 46:13-15
Several times a day: Dan 6:10; 1 Chr 16:37; Ps 119:164; Ac 3:1; Heb 10:25
On holy days: 2 Chr 8:12-13; Eze 46:3
At the three annual pilgrim festivals: Deut 16:16
Passover (or the Feast of Unleavened Bread): Ex 12:1-20; Lk 2:41
Pentecost (or the Feast of Weeks): Ex 34:22; Ac 2:1
The Feast of Tabernacles (or Ingathering): Ex 23:16; Lev 23:33-36; Nu 29:12-39; Dt 16:13-15
On the Day of Atonement: Lev 16:34; Ex 30:10; Lev 16:3-33; Lev 23:26-32
On Sabbath days: Lk 4:16; Lev 24:5-8; Nu 28:9-10
Some examples of spontaneous worship
In response to an awareness of the closeness of God: Ex 34:8; Jdg 7:15
In response to the experience of God’s mercy: Ex 4:29-31; 1Sa 1:19-28
In response to the presence and power of Jesus Christ: Mt 28:8-9; Mt 14:33; Lk 24:52