This was sung at our wedding and this particular group happens to be singing in one of my hometowns, Eugene, Oregon. (Note: The song doesn't last through the whole clip.) The song is 'Africa' by William Billings.
Now shall my inward joys arise,
And burst into a song;
Almighty love inspires my heart,
And pleasure tunes my tongue.
God, on His thirsty Zion’s hill,
Some mercy drops has thrown;
And solemn oaths have bound His love
To show’r salvation down.
Why do we then indulge our fears,
Suspicions and complaints?
Is He a God, and shall His grace
Grow weary of His saints?