1 John 2:27 says the anointing teaches truth and is not a lie, directly reinforcing the same contrast between truth and falsehood.

1 John 5:13 assures believers that they know they have eternal life, a result of knowing the truth mentioned in the main verse.

Romans 15:14 affirms believers are filled with knowledge and able to instruct—paralleling 1 John 2:21 where they know the truth and reject lies.

Romans 15:15 shows Paul writes to remind believers of what they know—exactly the same purpose as 1 John 2:21, where John writes because they already know truth.

In 2 Peter 1:12, Peter also writes to remind believers who already know the truth, reinforcing the idea that knowledge of truth is foundational.

In John 10:5, sheep flee from strangers because they do not know their voice, illustrating how knowing truth leads to rejecting lies.

2 John 1:1 opens by addressing 'all who know the truth,' using the same phrase and connecting directly to the readers' knowledge.

In Revelation 2:2, the church tests false apostles, echoing 1 John's theme of knowing truth and rejecting lies. Both emphasize discernment.