In its context, the prophet Zechariah in this passage is exhorting the people of Judah to turn from their idolatrous practice of attributing the blessing of rain to the false god Baal, and return to asking the Lord (YHWH), the true giver of rain, to give them the rain they needed for their sustenance.

What strikes me about this passage is that the prophet Zechariah is exhorting the people of Judah to ask God for something that they would probably be getting anyway: rain in the time of the spring rain.
Have you ever thought something like, “Why do I need to ask God for this? Doesn’t He know my needs? Doesn’t He already know my wishes and desires? Doesn’t He want to bless me? Why do I need to go through the process of asking Him for things He already knows that I want, and things which He probably already wants to give me?” Why ask God for rain when He is going to give the rain anyway? Why does God want us to pray to Him?

I believe there are at least three reasons why God wants us to spend time with Him in prayer, and ask Him for things He already knows about. The reasons can be categorized under the headings of Transformation, Fragrance, and Love.

Transformation
God is taking us through a process to transform us to be like Him. When we spend time with God in prayer, we are transformed, re-created so to speak, into His image. The more “face time” we spend with God in prayer, the more we are transformed. We get a glimpse of this truth when we read the account of the disciples experience with Jesus on the Mount of Transfiguration. Luke’s account tells us, “And while He (Jesus) was praying, the appearance of His face became different, and His clothing became white and gleaming.” (Luke 9:29). I realize that Jesus did not need to be changed; He was and is already the perfect reflection of who God the Father is. But I believe that when Jesus went up to the mountain to pray, and directed His attention from this world to His heavenly Father, He began to reflect the glory of the Father as He came into His presence; and this was what was being revealed to His disciples.*

Moses face was changed after spending 40 days and nights in the presence of God on Mt. Sinai (Ex. 24:12-18, 34:29-35). And the Apostle Paul relates this experience that Moses had to our experience as we come into the presence of the Lord:

“But we all, with unveiled face, beholding in a mirror the glory of the Lord, are being transformed into the same image from glory to glory, just as from the Lord, the Spirit”. 2 Cor. 3:18

The Apostle Paul also writes to the Colossians that they are to “put on” the new self, “who is being renewed (lit. renovated) to a true knowledge according to the image of the One who created him…”
Col. 3:10 NASB

When the human race fell in Adam’s transgression, the image of God in us was tarnished/distorted. When we are born again by faith, and indwelt by the Holy Spirit, God begins that work of renovation in us–like renovating a building–removing what is old and rotted, and replacing it with the new. We are being re-created in His image to be more like Him. Spending time with Him in prayer acts as a catalyst to move this process along. He doesn’t need us to pray, it’s the other way around. He wants to bless us, and cause us to reflect to the world around us what He is like! The was Adam’s original purpose: to be a reflection of the invisible God to the physical world. Adam failed in this, but Jesus, who is called “the last Adam” (1 Cor. 15:45) succeeded.

Fragrance
“For we are a fragrance of Christ to God…” (2 Cor. 2:15a)
When we come to God the Father in prayer, He “smells” the fragrant aroma of His Son on us. We manifest “the sweet aroma of the knowledge of Him” (2 Cor. 2:14). In other words, when we come to God through His Son, it brings pleasure to Him. God enjoys the pleasure of our company. We are His treasure, His inheritance. We are the reason He sent His Son to die on the cross. He loves it when we come to Him in prayer!

Love
Our Heavenly Father wants the best for us. He wants to transform us; He wants to spend time with us. He wants to include us in accomplishing His will “on earth as it is in heaven”. He wants to reward us for being involved in accomplishing His will on earth by building His church and reaching out to a lost world. He lets us pray to Him to accomplish these things; He lets us in on what He is doing; and He rewards us for playing a part in accomplishing His will.

Ask the Lord for rain in the season of spring rain. Don’t do it out of duty or obligation; do it to bring pleasure to Him.

*I recognize that there are other equally valid ways of interpreting this passage: namely that Jesus was simply unveiling His glory to His disciples at this event. I believe that these views are not mutually exclusive.