Charles Ellicott Commentary Genesis 24:21

"And the man looked stedfastly on her, holding his peace, to know whether Jehovah had made his journey prosperous or not." — Genesis 24:21 (ASV)

And the man wondering at her ... — The verb is rare, and the Septuagint, Syriac, and Vulgate, followed by Gesenius and Fürst, translate, “And the man gazed attentively at her, keeping silence, so that he might know,” etc.

The servant, we may well believe, was astonished at the exactness and quickness with which his prayer was being answered. However, this is not the primary focus of the rest of the verse. Instead, it presents him to us as keenly observing all she said and did, carefully concluding that the attractive and generous young woman was the destined bride for his master's son.