Acts 1:24

and they prayed, "O Lord, who readest the hearts of all, do thou single out from these two men him whom thou hast chosen

Acts 15:8

The God who reads the hearts of all attested this by giving them the holy Spirit just as he gave it to us;

Acts 6:6

these men they presented to the apostles, who, after prayer, laid their hands upon them.

Revelation 2:23

and her children I will exterminate. So shall all the churches know that I am the searcher of the inmost heart; I will requite each of you according to what you have done.

Luke 6:12-13

It was in these days that he went off to the hillside to pray. He spent the whole night in prayer to God,

John 2:24-25

Jesus, however, would not trust himself to them; he knew all men,

John 21:17

For the third time he asked him, "Simon, son of John, do you love me?" Now Peter was vexed at being asked a third time, "Do you love me?" So he replied; "Lord, you know everything, you can see I love you." Jesus said, "Then feed my sheep.

Acts 13:2-3

As they were worshipping the Lord and fasting, the holy Spirit said, "Come! set me apart Barnabas and Saul for the work to which I have called them."

Acts 14:23

They chose presbyters for them in every church, and with prayer and fasting entrusted them to the Lord in whom they had believed.

Romans 8:27

and He who searches the human heart knows what is in the mind of the Spirit, since the Spirit pleads before God for the saints.

Hebrews 4:13

And no created thing is hidden from him; all things lie open and exposed before the eyes of him with whom we have to reckon.

Treasury of Scripture Knowledge

Summary

And they prayed, and said, Thou, Lord, which knowest the hearts of all men, shew whether of these two thou hast chosen,

Bible References

They

Acts 13:2
As they were worshipping the Lord and fasting, the holy Spirit said, "Come! set me apart Barnabas and Saul for the work to which I have called them."
Luke 6:12
It was in these days that he went off to the hillside to pray. He spent the whole night in prayer to God,

Thou, lord

Acts 15:8
The God who reads the hearts of all attested this by giving them the holy Spirit just as he gave it to us;
John 2:24
Jesus, however, would not trust himself to them; he knew all men,
John 21:17
For the third time he asked him, "Simon, son of John, do you love me?" Now Peter was vexed at being asked a third time, "Do you love me?" So he replied; "Lord, you know everything, you can see I love you." Jesus said, "Then feed my sheep.
Hebrews 4:13
And no created thing is hidden from him; all things lie open and exposed before the eyes of him with whom we have to reckon.
Revelation 2:23
and her children I will exterminate. So shall all the churches know that I am the searcher of the inmost heart; I will requite each of you according to what you have done.