Numbers 9:3

9:3 In the fourteenth day of this month, at twilight, you are to observe it at its appointed time; you must keep it in accordance with all its statutes and all its customs.”

Numbers 9:7

9:7 And those men said to him, “We are ceremonially defiled by the dead body of a man; why are we kept back from offering the Lord’s offering at its appointed time among the Israelites?”

Numbers 28:2

28:2 “Command the Israelites: ‘With regard to my offering, be sure to offer my food for my offering made by fire, as a pleasing aroma to me at its appointed time.’

Numbers 29:39

29:39 “‘These things you must present to the Lord at your appointed times, in addition to your vows and your freewill offerings, as your burnt offerings, your grain offerings, your drink offerings, and your peace offerings.’”