1. (v. t.) To warn or notify of a fault; to reprove gently or kindly, but seriously; to exhort.
2. (v. t.) To counsel against wrong practices; to caution or advise; to warn against danger or an offense; — followed by of, against, or a subordinate clause.
3. (v. t.) To instruct or direct; to inform; to notify.*
“[Therefore beware] brethren, take care, lest there be in any one of you a wicked, unbelieving heart [which refuses to cleave to, trust in, and rely on Him], leading you to turn away and desert or stand aloof from the living God.
But instead warn (admonish, urge, and encourage) one another every day, as long as it is called Today, that none of you may be hardened [into settled rebellion] by the deceitfulness of sin [by the fraudulence, the stratagem, the trickery which the delusive glamor of his sin may play on him].
For we have become fellows with Christ (the Messiah) and share in all He has for us, if only we hold our first newborn confidence and original assured expectation [in virtue of which we are believers] firm and unshaken to the end.
Then while it is [still] called Today, if you would hear His voice and when you hear it, do not harden your hearts as in the rebellion [in the desert, when the people provoked and irritated and embittered God against them].”
Hebrews 3:12-14 AMPC
*Webster’s Revised Unabridged Dictionary