Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
There ought to be no division between Ecc 10:20 and Ecc 11:1.
As if in contrast to the self-indulgence described in Ecc 10:16-19, the opposite virtue, readiness to give to others, is inculcated. The use of the word "bread" in both Ecc 10:19 (see the note) and Ecc 11:1 points the contrast.
The verse means: "Show hospitality, even though the corresponding return of hospitality to you may seem improbable; nevertheless, be hospitable in faith." Compare Luk 14:13-14; Heb 13:2. Some interpreters (not unreasonably) understand by "bread" the seed from the produce of which bread is made. Seed cast upon the fertile soil flooded by the early rains would be returned to the sower in autumn with large increase.
The verse means: "Let your hospitality and your alms be extensive: for you know not what reverses may befall either that person who by your liberality will be strengthened to meet them, or yourself who may come to need grateful friends." Compare Luk 16:9.
Seven, and also to eight - A definite number for an indefinite (compare marginal reference).
"Unforeseen events come from God; and the man who is always gazing on the uncertain future will neither begin nor complete any useful work: but do thou bear in mind that times and circumstances, the powers of nature and the results to which they minister, are in the hand of God; and be both diligent and trustful." The images are connected chiefly with the occupation of an agricultural laborer: the discharge of rain from the cloud, and the inclination of the falling tree, and the direction of the wind, are beyond his control, though the result of his work is affected by them. The common application of the image of the fallen tree to the state of departed souls was probably not in the mind of the inspired writer.
Spirit - The same Hebrew word (like πνεῦμα pneuma in Greek and "Spirit" in English) signifies both the wind Ecc 11:4 and the Spirit (compare marginal reference). The Old Testament in many places recognizes the special operation of God Job 10:8-12; Psa 139:13-16; Jer 1:5, and distinctly of the Spirit of God Job 31:15 in the origination of every child. Compare Gen 2:7.
The preceding exhortation to a life of labor in the sight of God is now addressed especially to the active and the young; and is enforced by another consideration, namely, the transitory character of all that sustains youth.
The light ... the sun - Gifts of God which cheer man's toil, but which he almost ceases to appreciate in his old age.
Days of darkness - The time of old age, and perhaps any time of sorrow or misfortune. Compare Ecc 12:2.
All that cometh - i. e., "The future," which must not be reckoned on by the active man, as if his present state of healthy energy were to continue.
Rejoice ... cheer ... walk - The imperative mood is used to encourage one who possesses certain gifts from God to remember that they come from God and are to be used in accordance with His will.
In the ways ... - The words are probably used in an innocent sense Ecc 2:10; Pro 16:9.
Judgment - This includes a judgment beyond the grave; though the writer's view of it was dim and indefinite if compared with Christian's.
The sense appears to be, "Let the timely recollection of God's judgment, and of the fleeting character of youth, so influence your conduct that you will refrain from acts which entail future remorse and pain."