Today is Harvest Festival in Sabah, the first of two-day public holidays. It is the major festival of the majority group of the indigenous peoples of Sabah, the Kadazan-Dusuns. It coincides with Pentecost Sunday which is also a harvest festival (Lev 23:9-11) when first fruits are harvested and sheaves of wheat are gathered from the fields (Lev 23:10). It is also called the feast of Weeks (Deut 16:10) because Pentecost (as the Greek word indicates) falls on the 50th day after Passover, which is after 7 weeks (7x7) in total.
It is a thanksgiving feast where we are to thank God for the blessings He has blessed us with and in return we offer a free-will or voluntary offering unto the Lord (Deut 16:10). For all His blessings, we are to rejoice in His presence and bless our children, Levites in our midst, foreigners who live among us and the poor, widows and orphans. It is also a feast to remember full-time church workers (Levites of today) and honour them by blessing them with our blessings which we received from the Lord.
The waiving for the first sheaf of wheat (Lev 23) signifies the first fruits which harvests are to follow - wheat and later in the year, grapes and olives at the Feast of Tabernacles. The waiving of the sheaves is also a sign of the Pentecost, not just as a wave offering unto the Lord for all His goodness but on the first Pentecost after Jesus died, rose again and ascended into heaven, His disciples were filled with the Holy Spirit and they moved like the sheaves of wheat being waved (observers thought that they were drunk - Acts 2:13) before the Lord as the first fruits of the nascent church when on the day of Pentecost 3,000 souls were converted. Pentecost is now remembered as the day of the coming of the Holy Spirit by which the church was born and founded in 30AD.