Deuteronomy 16:16
Three times in a year shall all thy males appear before the LORD thy God in the place which he shall choose; in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles: and they shall not appear before the LORD empty H7387

Empty - Strong's H7387 – rêqām (ray-kawm'
vainly, emptily, in empty condition, empty, in vain, WITHOUT EFFECT, WITHOUT CAUSE
Brown-Driver-Briggs
1. in empty condition, empty = with empty hands, with verb of sending, without an offering
2. in vain, without effect

Genesis 1:14-19
14 And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs H226, and for seasons H4150, and for days, and years:

Signs - Strong's H226 - 'ôṯ (oth)
sign, signal, a distinguishing mark, BANNER, remembrance, miraculous sign, omen, warning, token, ensign, standard, miracle, proof

Banner - Strong's H5251 – nēs (nace)
something lifted up, standard, signal, signal pole, ensign, banner, sign, sail, STANDARD (AS RALLYING POINT), signal, standard (pole), ensign, signal

Seasons - Strong's H4150 - môʿēḏ (mo-ade'
appointed place, appointed time, meeting, sacred season, set feast, appointed season, appointed sign or signal, tent of meeting
BY IMPLICATION, AN ASSEMBLY (AS CONVENED FOR A DEFINITE PURPOSE)

The Moedim are appointed Rallying Points, appointed times to come together for a definite purpose. We are children of the light. We should not be gathering during these times in vain. We should not be gathering during these times without effect, without a cause, without a definite purpose. These are appointed times to bring your meat offerings, your drink offerings, your freewill offerings and make your vows. These are appointed times to redeem your brother from their debt to the heathen. These are appointed times for Israel to bring their money together to build the wall and repair the breach.