Claude found the lyrics and sent them to me by personal message. Here's what I found at this site (click), which has lots of Leadbelly lyrics:

GIT ON BOARD

Oh, watch you gwine-a do,
With those motherless chillun?
Watch you gwine-a do,
With those motherless chillun, ooh?
Watch you gwine-a do,
With those motherless chillun,
Git on board, git on board.

I’m gonna take ‘em by the hand, ooh,
And lead ‘em to Jesus,
I’m gonna take ‘em by the hand,
And lead ‘em to Jesus.
Oh take ‘em by the hand,
And lead ‘em to Jesus.
Git on board, git on board.

“Now sisters and brothers, you know when you get ready to go to Christ, you got to come to Jesus. Got to come to the mourner’s bench before you get ready to go to Christ. Let ‘em know what you bowing down there for. You get down on their knees, get down in your way, when you get down on your knees, brothers and sisters, you get down and pray. And when you get ready to go to Christ, you got to think about Christ. You can’t go to Christ without thinkin’ about Christ—,

Take ‘em by the hand,
And lead him to Jesus.
Oh, take ‘em by the hand,
And lead him to Jesus.
Oh, take ‘em by the hand,
And lead him to Jesus,
Git on board, git on board.

Oh, Jesus was a giant,
Oh, and lead him to Jesus,
Hang ‘em on the josh, {rafters or beams}
And lead him to Jesus.
Oh, hang ‘em on the josh,
And lead him to Jesus,
Git on board, git on board.

“Now, ladies and gentlemen, if you want to see Christ and want to go by and talk with Jim a little while. If you don’t get to Jim, you wanna stop and talk with Thiera a little bit and (if) you can’t talk with Theira you got to stop and talk with Jim a little while. All of ‘em hangin’ on the road for Christ. When readin’ the bible say, Amen.”

Ain’tcha gonna tell, ‘
Bout then Hebrew chillun,
Ain’tcha gonna tell,
‘Bout them Hebrew chillun,
Oh, yes I’m gwine-a tell, ‘
Bout them Hebrew chillun,
Git on board, git on board, ooh!