Jamieson, Fausset and Brown on Ecclesiastes 9:11

11. This verse qualifies the sentiment, Ec 9:7-9. Earthly "enjoyments," however lawful in their place (Ec 3:1), are to give way when any work to be done for God requires it. Reverting to the sentiment (Ec 8:17), we ought, therefore, not only to work God's work "with might" (Ec 9:10), but also with the feeling that the event is wholly "in God's hand" (Ec 9:1).

race ... not to the swift--(2Sa 18:23); spiritually (Zep 3:19; Ro 9:16).

nor ... battle to ... strong--(1Sa 17:47; 2Ch 14:9, 11, 15; Psa 33:16).

bread--livelihood.

favour--of the great.

chance--seemingly, really Providence. But as man cannot "find it out" (Ec 3:11), he needs "with all might" to use opportunities. Duties are ours; events, God's.