Deuteronomy 16:16-17

Now three times a year here refers to the three holy day seasons, particularly the three pilgrimage festivals where the Israelites would all come up to Jerusalem to the Tabernacle or to Jerusalem, the Temple, and they literally came before God. They presented themselves, as it were, before His throne, which the mercy seat depicts, and they would give offerings. Now, we do this on the seven annual holy days within those three seasons, when we come before God spiritually in holy convocation.

One thing we need to note here is that God does not set a fixed amount. We are to contemplate, think it through how much God has blessed us in the past year. And even longer term, it does not need to be just the past year. But He wants us to sit down and really come to understand how much He has made a difference in our lives, how much we owe Him and acknowledge that through an offering. Now, he gives no figure. He does not say you are to give $100 for each blessing. He does not do that at all. He says, you think about it, you fix a price on it, you fix a value upon God having called you, given you this precious knowledge, and done all the work for you up to a certain point. It is a lot of work that He did and a very little amount that we actually have to do.