In a scripture passage, often there is a little letter at the beginning of the passage, indicating that there is a cross reference.
For example: In John 15:4, there is a "d" at the beginning of the passage. If you click on the "d", the cross references show up as "John 17:23; Eph. 3:17; [Col. 1:23]".
What do the brackets "[" around Col. 1:23 mean?
Depends upon the version you are using. Which version are you asking about?
Orthodox Bishop Hilarion Alfeyev: "To be a theologian means to have experience of a personal encounter with God through prayer and worship."
I believe this is referring to the NKJV - but there doesn't seen to be any explanation there as to what it means
A likely answer:
reddit: I've been able to find something about square brackets from Thomas Nelson's other bibles, I am assuming this philosophy is consistent across all of their bibles Cross-References. In addition to the references under many of the text subheadings, an extensive set of cross-references is included in the center of the bottom part of each page. (Placing the cross-references at the bottom allows for wider text column at the top, enhancing readability of the text.) Cross-references that are enclosed in square brackets identify passages similar in concept to the referenced passage in the text. The cross-references are indicated in the text by raised letters.
I've been able to find something about square brackets from Thomas Nelson's other bibles, I am assuming this philosophy is consistent across all of their bibles
Cross-References. In addition to the references under many of the text subheadings, an extensive set of cross-references is included in the center of the bottom part of each page. (Placing the cross-references at the bottom allows for wider text column at the top, enhancing readability of the text.) Cross-references that are enclosed in square brackets identify passages similar in concept to the referenced passage in the text. The cross-references are indicated in the text by raised letters.
NKJV