Romans 7:18 NKJV
For I know that in me (that is, in my flesh) nothing good dwells; for to will is present with me, but how to perform what is good I do not find.
But in other modern translations it is not bracketed
Romans 7:18 ESV
For I know that nothing good dwells in me, that is, in my flesh. For I have the desire to do what is right, but not the ability to carry it out.
Romans 7:18 DARBY
For I know that in me, that is, in my flesh, good does not dwell: for to will is there with me, but to do right [I find] not.
Romans 7:18 YLT
for I have known that there doth not dwell in me, that is, in my flesh, good: for to will is present with me, and to work that which is right I do not find,
Why is this phrase bracketed in the NKJV?