Lyrics: Fanny Crosby, 1873.

Music: Phoebe Knapp, 1873. Mrs. Knapp was the wife of Joseph Knapp, founder of the Metropolitan Life Insurance Company.

Theme: Let us draw near to God with a sincere heart in full assurance of faith, having our hearts sprinkled to cleanse us from a guilty conscience and having our bodies washed with pure water. Hebrews 10:22.

Crosby was visiting her friend Phoebe Knapp as the Knapp home was having a large pipe organ installed. The organ was incomplete so, using the piano, Mrs. Knapp played a new melody she had just composed called “Assurance”. “What do you think the tune says?” asked Knapp.
“Blessed assurance, Jesus is mine”, answered Fanny Crosby.

Blessed assurance, Jesus is mine!
O what a foretaste of glory divine!
Heir of salvation, purchase of God,
Born of His Spirit, washed in His blood.

Refrain:
This is my story, this is my song,
praising my Savior all the day long;
this is my story, this is my song,
praising my Savior all the day long.

Perfect submission, perfect delight!
Visions of rapture now burst on my sight;
Angels descending bring from above
Echoes of mercy, whispers of love.

Perfect submission, all is at rest!
I in my Savior am happy and blest,
Watching and waiting, looking above,
Filled with his goodness, lost in His love.

This hymn marks Ms. Crosby’s fifth and final appearance on this list. Other Top 100 Hymns by Fanny Crosby are:

To God Be the Glory
Redeemed How I Love to Proclaim It
All the Way My Saviour Leads Me
Tell Me the Story of Jesus

More about Fanny Crosby.
More about Phoebe Knapp.
Lifespring Hymn Stories: Blessed Assurance.