Ira Sankey, D.L. Moody’s songleader, discovered Stockton’s song in 1873 before it was published. It is said that the original lyrics in the refrain repeated the words, “Come to Jesus” three times and that Sankey altered the lyrics to the version we know: “Only trust Him.” According to some sources, Sankey is credited with composing the music and the lyrics for the refrain.

The "core gospel message," as Andrew describes it, is clear in the text, and it's obvious why it would have appealed to the evangelistically-minded Sankey:
Come, every soul by sin oppressed;
There’s mercy with the Lord,
And He will surely give you rest
By trusting in His Word.
For Jesus shed His precious blood
Rich blessings to bestow;
Plunge now into the crimson flood
That washes white as snow.
Yes, Jesus is the truth, the way,
That leads you into rest;
Believe in Him without delay
And you are fully blessed.
The last verse of Andrew's arrangement is one my favorite parts. It demonstrate a deft musical touch and an awareness of the text. As Andrew explains, "I always hope to present the words clearly in my arrangements - while illustrating the text with the music. For instance - "come then and join this holy band" the men present the invitation, while you can hear the "band" singing in the women's parts."
Come, then, and join this holy band,
And on to glory go
To dwell in that celestial land
Where joys immortal flow.
The ending is a beautifully tender moment, rich in texture and deep in meaning. "I remember enjoying the process of writing the ending," Andrew recalls. "Instead of "amens" in canon, being able to repeat the core message of the mercy found in Jesus. That, for me, is the heart of this hymn - reassurance that despite our flaws and failures, our trust is well-founded - there's mercy with the Lord."
Only trust Him, only trust Him,
Only trust Him now;
He will save you, He will save you,
He will save you now.