In Revelation 3 we read that the church in Philadelphia was a faithful church. The elder was faithful, and so the church was faithful. The Lord told them, I have put before you an open door which nobody can shut" (Rev. 3:8).
When the Lord opens a door for us nobody can shut it. He says, "I have the keys. I open and no man can shut" (Rev. 3:7). We don't have to go banging away at any door. Our Lord opens the right ones for us, without our even touching them. They are like the automatic doors that we have seen in some airports that open as soon as you come near them. Are you looking for a door of ministry for yourself? Are you trying to open such a door for yourself or looking to some influential man to open that door for you? Are you coveting the ministry that someone else has? That is evil.
Be faithful to God in the little things and He will open the right doors of ministry for you at the right time. Then you won't waste your time or your life, going through many wrong doors. Trust in God and let Him alone open the doors for you - and He will lead you step by step to the places that He has planned for you.
I remember once when I was travelling to a certain country the Lord said to me, "You are not to write to anyone you know in that country that you are going there. Just go." I went there and had no ministry anywhere - and I came back. The Lord tested me to see if I would obey Him. The next time I went to that country, the Lord opened so many doors to people I did not even know. Those were the places that the Lord wanted me to go to. I saw then that God in His sovereignty opens the right doors. If I had tried to open doors by myself earlier, to create some ministry for myself, I would have missed the will of God completely. So don't ever push yourself forward anywhere. Wait on God and let Him open the right doors for you. Like the ones in Philadelphia, you may have just a little strength. But if you keep God's Word and do not deny His Name, the Lord will make even your enemies recognise that He has loved you (Rev. 3:8, 9).
Then the Lord told this church, "I am coming quickly. Hold fast what you have so that nobody takes your crown" (Rev.3:11). When the Lord gives us a ministry, we must be faithful in fulfilling it. Otherwise He will give that ministry to someone else and then that person will get the crown that was meant for you! He will get his crown and yours as well. So be faithful. The Lord will make those who overcome "pillars in His church" (Rev 3:12 ). Pillars are what hold up a building. When Samson pushed down two pillars, the whole building collapsed. Sometimes there are only two elders who hold up a whole church. When they die, the church dies as well. God wants many pillars in His churches. You can be a pillar, if you seek to overcome sin in your private life and in your thoughts.