Here are 5 Bible verses about open doors from the Old and New Testaments of the Holy Bible (King James Version), sorted from most to least relevant.
Isaiah 45:1 KJV
Thus saith the LORD to his anointed, to Cyrus, whose right hand I have holden, to subdue nations before him; and I will loose the loins of kings, to open before him the two leaved gates; and the gates shall not be shut;
Revelation 3:7-8 KJV
And to the angel of the church in Philadelphia write; These things saith he that is holy, he that is true, he that hath the key of David, he that openeth, and no man shutteth; and shutteth, and no man openeth; I know thy works: behold, I have set before thee an open door, and no man can shut it: for thou hast a little strength, and hast kept my word, and hast not denied my name.
Isaiah 22:22 KJV
And to the angel of the church in Philadelphia write; These things saith he that is holy, he that is true, he that hath the key of David, he that openeth, and no man shutteth; and shutteth, and no man openeth; I know thy works: behold, I have set before thee an open door, and no man can shut it: for thou hast a little strength, and hast kept my word, and hast not denied my name.
2 Corinthians 2:12 KJV
And the key of the house of David will I lay upon his shoulder; so he shall open, and none shall shut; and he shall shut, and none shall open.
1 Corinthians 16:9 KJV
Furthermore, when I came to Troas to preach Christ’s gospel, and a door was opened unto me of the Lord,