Loosely translated the hymn gives thanks to God, our creator, and acknowledges His selfless love for us.
The chorus praises that idea: "Let us sing hallelujah and thank you. Let us sing hallelujah and thank you.''
The second part of the song is particularly poignant and meaningful to Manu Samoa's gesture to the former South African rugby great.
The verse calls for those facing difficult times in their lives to seek refuge and solace in God's only son, Christ.
The post accompanying the video reads: "Totally humbling experience to meet Springboks legend Joost Van Der Westhuizen in Brighton today. This man does not let Motor Neuron Disease define him or stop him living life to the fullest. This hymn seemed right for the occasion."
The post has attracted more than 350 comments and has been shared more than 3000 times.
Van der Westhuizen made 89 appearances for the Springboks over 10-years between 1993 and 2003, including South Africa's 1995 World Cup final win over the All Blacks.