If we knock, God will open what we are knocking on  -  Matthew 7:7

Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you:

If verse 7 is taken out of context, it seems that we can get whatever we ask for, but that is not Biblical. To receive anything from God – 1) we are not to have any unconfessed sin in our life  (Psalm 66:18), 2) we are to pray in faith  (James 1:6), 3) we must ask according to the will of God  (1 John 5:14), 4) we must ask persistently  (Luke 18:1). In the third statement of verse 7, Jesus said to knock. So…we are to knock, and keep on knocking, until whatever we are standing in front of, opens.