Albert Barnes Commentary Acts 1:24

"And they prayed, and said, Thou, Lord, who knowest the hearts of all men, show of these two the one whom thou hast chosen," — Acts 1:24 (ASV)

And they prayed. As they could not agree on the individual, they invoked the direction of God in their choice—an example which should be followed in every selection of an individual to exercise the duties of the sacred office of the ministry.

Which knowest the hearts of all men. This is often declared to be the unique prerogative of God. Jeremiah 17:10, I, Jehovah, search the heart; Psalms 139:1, 23; 1 Chronicles 28:9.

Yet this attribute is also expressly ascribed to Jesus Christ. Revelation 2:18, 23, These things saith the Son of God—I am he which searcheth the reins and hearts.John 2:25; John 6:64; John 16:19.

There are strong reasons for supposing that the apostles on this occasion addressed this prayer to the Lord Jesus Christ.

1. The name Lord is the common appellation which they gave to him, Acts 2:36; Acts 7:59, 60; Acts 10:36; 1 Corinthians 2:8; Philippians 2:11; Revelation 11:8.
2. We are told that they worshipped him, or rendered him divine honours after his ascension, Luke 24:52.
3. The disciples were accustomed to address him after his crucifixion by the names Lord or God indifferently, Acts 1:6; John 20:28; Acts 7:59.
4. This was a matter pertaining especially to the church which the Lord Jesus had redeemed, and to his own arrangement in regard to it. He had chosen the apostles; he had given their commission; he had fixed their number; and what is worthy of special remark here, he had been the companion of the very men, and knew their qualifications for their work.

If the apostles ever called on the Lord Jesus after his ascension, this was the case in which they would be likely to do it. That it was done is clear from the account of the death of Stephen, Acts 7:59, 60. And in this important matter of ordaining a new apostle to be a witness for Jesus Christ, nothing was more natural than that they should address him, though bodily absent, as they would assuredly have done if he were present.

And if on this occasion they did actually address Christ, then two things clearly follow.

1. That it is proper to render him Divine homage, in accordance with the uniform declarations of the Scriptures. John 5:23, That all men should honour the Son, even as they honour the Father.Hebrews 1:6, And let all the angels of God worship him.Philippians 2:10, 11; Revelation 5:8–14; 1 Thessalonians 3:11, 12.
2. He must be Divine. To no one but God can religious homage be rendered; and no one else can be described as knowing the hearts of all men. The reason why they appealed to him on this occasion as the Searcher of the heart was doubtless the great importance of the work to which the successor of Judas was to be called. One apostle of fair external character had proved a traitor; and with this fact full before them, they appealed to the Saviour himself, to select one who would be true to him, and not bring dishonour on his cause.

Shew whether, etc. Show which of them.

Thou hast chosen. Not by any public declaration, but which of the two you have judged to be best qualified for the work, and have fitted for it.