Blessed Assurance includes in three different keys:

C major, B flat major and D major.

Each major keys has a total of 10 arrangements.

Why in many different keys:
This series is designed for hymn lovers to enjoy playing the hymns they love. Some player loves to sing along with the lyrics.
For the singing purpose: For the human vocal, we can only reach a certain pitch. In general, most of humans (not includes professional trained or gifted singers) can only reach high E. The high E is E5 on the piano keys. However, some people have hard time singing over high C which is C5 on piano keys.
For playing purpose: C major is the easiest key to play with. There are no keys signatures. Only a few or no black keys involve in C major. Therefore,  you will see C major on all hymn arrangements. However, in some hymns, it is too hard for a player to sing along with C major. Because some melody has notes higher than high C (C5).
You can choose the suitable keys for play and sing along together. If you want to play only, C major will your best choice.

Watch the arrangements on Youtube

Click here to see more arrangements on the Youtube Channel.

Blessed Assurance 01: Melody only

Blessed Assurance 02: LH one note accompany

Blessed Assurance 03: LH simple chords accompany

Blessed Assurance 05: LH inverted chords

Blessed Assurance 06: LH simple broken chords

Blessed Assurance 07: LH broken inverted chords

Blessed Assurance 08: LH broken inverted chords accompany style 1