Interesting verse, filled with great meaning. It stands alone as an exhortation to petition God for what we really want or need and a charge to keep asking!
But, there is more here, as the context shows...
Matthew, Chapter 7 (WEB)
7 “Ask, and it will be given you. Seek, and you will find. Knock, and it will be opened for you. (emphasis added vs.7) 8 For everyone who asks receives. He who seeks finds. To him who knocks it will be opened. 9 Or who is there among you, who, if his son asks him for bread, will give him a stone? 10 Or if he asks for a fish, who will give him a serpent? 11 If you then, being evil, know how to give good gifts to your children, how much more will your Father who is in heaven give good things to those who ask him! 12 Therefore whatever you desire for men to do to you, you shall also do to them; for this is the law and the prophets. (emphasis added vs.12)
The widest context of this passage (commonly called the "sermon on the mount") could be labeled "to be a genuine disciple of God". The narrower context (these few verses) emphasizes God's graciousness in granting the needs of those that reach out to HIM and our imitation of HIS practices. Be like God; he wants you ask, see and knock. He wants the very best for us all, HIS motives are always in our best interest because HE loves US!!!
Even though the graphic displays the verse as being in the sky, it is not a "pie in the sky" concept, but rather a "down to earth" one. Be close to God and HE will be close to you! Believe it, because its right!!!