This is how Jonathan Edwards described his experience of listening to David Brainerd pray:
We enjoyed not only the benefit of his conversation, but had the comfort and advantage of hearing him pray in the family, from time to time. His manner of praying was very agreeable; most becoming a worm of the dust, and a disciple of Christ, addressing an infinitely great and holy God, and Father of mercies; not with florid expressions, or a studied eloquence; not with any intemperate vehemence, or indecent boldness. It was at the greatest distance from any appearance of ostentation, and from everything that might look as though he meant to recommend himself to those that were about him, or set himself off to their acceptance. It was free also from vain repetitions, without impertinent excursions, or needless multiplying of words. He expressed himself with the strictest propriety, with weight, and pungency; and yet what his lips uttered seemed to flow from the fullness of his heart, as deeply impressed with a great and solemn sense of our necessities, unworthiness, and dependence, and of God's infinite greatness, excellency, and sufficiency, rather than merely from a warm and fruitful brain, pouring out good expressions.
And I know not that ever I heard him so much as ask a blessing or return thanks at table but there was something remarkable to be observed both in the matter and manner of the performance. In his prayers, he insisted much on the prosperity of Zion, the advancement of Christ's kingdom in the world, and the flourishing and propagation of religion among the Indians. And he generally made it one petition in his prayer, "that we might not outlive our usefulness."
— The Life and Diary of David Brainerd, p. 349 —