New Revised Standard Version
Joab said to him, “You are not to carry tidings today; you may carry tidings another day, but today you shall not do so, because the king’s son is dead.”

Contemporary English Version
Joab answered, "You're not the one to tell the king that his son is dead. You can take him a message some other time, but not today."

New American Bible
But Joab said to him: “You are not the man to bring the news today. On some other day you may take the good news, but today you would not be bringing good news, for in fact the king’s son is dead.”

Douay-Rheims Bible
And Joab said to him: Thou shalt not be the messenger this day, but shalt bear tidings another day: this day I will not have thee bear tidings, because the king's son is dead.

And Joab said to him: Thou shalt not be the messenger this day, but shalt bear tidings another day: this day I will not have thee bear tidings, because the king's son is dead.

bear tidings [heb] be a man of tidings

2 Samuel 17:16-21 Now therefore send quickly, and tell David, saying: Tarry not this night in the plains of the wilderness, but without delay pass over: lest the king be swallowed up, and all the people that is with him. . . .

because

2 Samuel 18:5,27,29,33 And the king commanded Joab, and Abisai, and Ethai, saying: Save me the boy Absalom. And all the people heard the king giving charge to all the princes concerning Absalom. . . .