Feasting and Fasting
The people had been observing a fast every year in the fifth month to commemorate the destruction of the temple by Nebuchadnezzar. Now that the temple was being rebuilt, they wanted to know if they should still fast. The Lord asked them why they were fasting in the first place. "Did you really fast for Me - for Me?" The implication is that they were really doing it for themselves. He then went on to point out that all their feasts were also just for themselves, not for God.
Spiritual exercises can so often just become routine and meaningless. And we must guard against any practice within the church becoming just a meaningless habit. We can go through the motions, but lose the emotion. On Thanksgiving, are we thinking about God, and all He has done for us; or is it about turkey, family and football? When we sing praises to God, is it real worship or just a performance or a chance for the latecomers to find a seat? When we participate in the Communion, are we really communing with Jesus, or is it just crackers and juice?
God was questioning the people on this. "Yes, you performed all the rituals, but where was your heart? Were you really communing with Me?"