Charles Ellicott Commentary Acts 5:9

"But Peter [said] unto her, How is it that ye have agreed together to try the Spirit of the Lord? behold, the feet of them that have buried thy husband are at the door, and they shall carry thee out." — Acts 5:9 (ASV)

To tempt the Spirit of the Lord—that is, to try, or test, whether the Spirit that lived in the Apostles could truly discern the secrets of human hearts. The “Spirit of the Lord” is probably used in its Old Testament sense, as the Spirit of Jehovah. This combination is rare in the New Testament, occurring only in 2 Corinthians 3:17, but is common in the Old Testament, as in Isaiah 61:1 ; 1 Kings 22:24; 2 Kings 2:16.

Behold, the feet of them. . . .—In this instance, the coming judgment is foretold, and the announcement helped bring about its own fulfillment. Here, to all the shame and agony that had fallen on Ananias, there was now added the bitter thought of her husband’s death as in some sense caused by her, since she might have prevented the crime that led to it. The prophetic insight given to Saint Peter taught him that the messengers, whose footsteps he already heard, had another similar task before them.