Daniel 1:16

Then let our faces be examined before you, and the face of the youths who eat of the king’s delicacies; and as you see, deal with your servants.”

So he listened to them in this matter, and tested them for ten days.

At the end of ten days, their faces appeared fairer and they were fatter in flesh than all the youths who ate of the king’s delicacies.

Now as for these four youths, God gave them knowledge and skill in all learning and wisdom; and Daniel had understanding in all visions and dreams.

At the end of the days which the king had appointed for bringing them in, the prince of the eunuchs brought them in before Nebuchadnezzar.

The king talked with them; and among them all was found no one like Daniel, Hananiah, Mishael, and Azariah. Therefore they stood before the king.