First, you need to know that the whole of Psalm 23 is completely, thoroughly and totally mistranslated in the KJV / NIV and the septuagint.
Not just simple mistranslation. Gross mistranslation and total misunderstanding of the Hebrew of the Psalm by your English/Greek translators. Not only are they guilty of syntactic ignorance, they have added concepts not found in the original Hebrew of the Psalm.
Mangling of verse 6 is the worst sin the translators committed against this Psalm.
IF you can bear some dry scriptural analysis of the Psalm, read this posting in my blog:
Let me reproduce the part of my blog that concerns your question
Verse 4: כי אתה עמדי
for You are with me
Alternatively, it can be translated as
for You are my uprightness, my withstanding stability, my standup-ness.
Due to absence of vowels,
could be either mean
im-adi (with me)
amidi (my standing-up)
where עמד = root for stand or located.
Remember the movie The Standup Guys. The LORD is my standing-up-ness.
Verse 4 again: שבטך ומשענתך המה ינחמני
Your sceptre / rod / tribe and your providing-support they comfort-console me.
What many people do not realise (because unfortunately they don't read the Bible in Hebrew), the word שבט could be used to mean a tribe or a rod or a sceptre of leadership. שבט is mostly used in the Bible to mean tribe. Therefore, שבט could mean having a dominant position as a leader.
I want to say, that שבט when used to mean tribe, actually means a column of people. Like in modern English (and Mathematics), a branch is used to denote a division or segment.
שען means a support.
משען is to provide support
משענת is the participle = the providing of support
Therefore a walking stick or a super-grandiose regal looking staff can be called a [משענת]. But in this case, משענת means exactly what it means - G'd providing support.
נחם is to comfort and console.
Your domain / leadership and your providing-support they comfort-console me.
Your assertive leadership and your being a support, they console and assure me.