What is it, Lord— That is, "Protect me from all danger, and let me know the meaning of this vision." The expression thy prayers, &c. are come up for a memorial, has reference to the incense offered under the law, which ascended in fumes, when burned; and implies that the prayers and alms of Cornelius were more grateful than the stream of burnt incense, or of the most costly sacrifice which he could have offered.
Related Commentaries of Acts 10:4
Acts 10:4
4 And when he looked on him, he was afraid, and said, What is it, Lord? And he said unto him, Thy prayers and thine alms are come up for a memorial before God.