Charles Spurgeon Commentary Zechariah 7:4-5

"Then came the word of Jehovah of hosts unto me, saying, Speak unto all the people of the land, and to the priests, saying, When ye fasted and mourned in the fifth and in the seventh [month], even these seventy years, did ye at all fast unto me, even to me?" — Zechariah 7:4-5 (ASV)

There is the point. You can fast to self. You can fast to your own pride. If we have no thought of honouring God in our fasting, there is nothing in it. The question is, Did ye at all fast unto me, even to me?