In Revelation 3:7,8, God who is described as "holy" and "true" is also said to be the One who "openeth, and no man shutteth; and shutteth, and no man openeth." This great Sovereign goes on to say, "behold, I have set before thee an open door and no man can shut it." Think of it, God has set before His people an "open door."
First of all, He sets before us the open door of fellowship. We who are unholy and untrue fellowshipping with God who is holy and true. Can this be? Yes, by the grace of God and through the blood and righteousness of the Lord Jesus Christ, we have entrance to the presence of God. On Christs merits we come boldly to the throne of grace. The weakest saint may pray and have audience with Him who sits upon the throne. Since prayer is a matter of the heart, no place, position or power can keep us from God. It cannot be legislated in or out of any place or time, not even school! No man can close this open door by which we are invited to come and commune with our Lord.
Secondly, God gives us an open door to the marvels of His Word. No priest or preacher can bar the believer who longs for truth from the riches of the Word of God. "If any man will do his will, he shall know of the doctrine." (John 7:17) The Spirit of God will reveal it! (I Cor. 2:7-12) Take the Bible in your hand and read it, praying to God for light as you go. The door of revelation will swing open wide and the most ignorant believer shall enter into the hidden riches of the mysteries of God. He shall tread where theologians and religious know-it-alls shall never set their foot. All because God opens the door!
Then also God will open the door of service for His people. It will be a way that will bring glory to Him and not to us. We by nature hesitate to enter the door that leads to obscurity for us; but in some place and in some way, little or great, He will open a way for us to be messengers of the gospel of His grace and glory. Whether it be as the servant girl in Naamans household or as a statesman such as Daniel, let us enter, not trying to create an open door of service but passing through the one He has opened. May we bloom where He plants us and shine that others might see Him!
It is a comforting and encouraging thing to know that when our God opens, no one can shut. May He in grace give us eyes to see and faith to enter in!