matthew 2:7 Then Herod, when he had privily called the wise men, enquired of them diligently what time the star appeared. - Free Bible Online

      The Wise Men Despatched to Bethlehem by Herod to See the Babe, and Bring Him Word, Make a Religious Offering to the Infant King, but Divinely Warned, Return Home by Another Way (Mt 2:7-12).

      7. Then Herod, when he had privily called the wise men--Herod has so far succeeded in his murderous design: he has tracked the spot where lies his victim, an unconscious babe. But he has another point to fix--the date of His birth--without which he might still miss his mark. The one he had got from the Sanhedrim; the other he will have from the sages; but secretly, lest his object should be suspected and defeated. So he
      inquired of them diligently--rather, "precisely."
      what time the star appeared--presuming that this would be the best clue to the age of the child. The unsuspecting strangers tell him all. And now he thinks he is succeeding to a wish, and shall speedily clutch his victim; for at so early an age as they indicate, He would not likely have been removed from the place of His birth. Yet he is wary. He sends them as messengers from himself, and bids them come to him, that he may follow their pious example.

JFB.