Isa 58:7 Deal thy bread to the hungry, and bring the needy and the harbourless into thy house: when thou shalt see one naked, cover him, and despise not thy own flesh.
Deal thy bread to the hungry. Literally, divide up thy bread among the hungry. What is the point of keeping bread your not eating during a fast? Those who have “stuff” by the bounty of God ought to share it with those who have not. The devout man should be a horn of plenty to others. On The Development Of Peoples, art. 23~“If someone who has the riches of this world sees his brother in need and closes his heart to him, how does the love of God abide in him?” (1 Jn 3:17). It is well known how strong were the words used by the Fathers of the Church to describe the proper attitude of persons who possess anything towards persons in need. To quote Saint Ambrose: “You are not making a gift of your possessions to the poor person. You are handing over to him what is his. For what has been given in common for the use of all, you have arrogated to yourself. The world is given to all, and not only to the rich.”
Despise not thy own flesh. Your fellow man of flesh and blood.
Isa 58:8 Then shall thy light break forth as the morning, and thy health shall speedily arise, and thy justice shall go before thy face, and the glory of the Lord shall gather thee up.
Then shall thy light break forth as the morning. Light here probably means prosperity (see Isa 9:1, 60:1-3; Job 11:17). 2 Cor 9:6-10~The point is this: he who sows sparingly will also reap sparingly, and he who sows bountifully will also reap bountifully. Each one must do as he has made up his mind, not reluctantly or under compulsion, for God loves a cheerful giver. And God is able to provide you with every blessing in abundance, so that you may always have enough of everything and may provide in abundance for every good work. As it is written, “He scatters abroad, he gives to the poor; his righteousness endures for ever.” He who supplies seed to the sower and bread for food will supply and multiply your resources and increase the harvest of your righteousness.
And thy health shall speedily arise. The word translated here as health refers to the healing of a wound, probably a reference to the ending of God’s punishment (see the image of punishment in Isa 1:5-6).
And thy justice shall go before thy face, and the glory of the Lord shall gather thee up. “Thy justice” is a reference to God, “the Lord our righteousness” (see Jer 23:6; 33:16). The phrases “go before thy face” and “the glory of the Lord shall gather thee up” suggest the protection of the the divine presence (see Isa 52:12; Ex 13:21-22). Further, the phrase “gather thee up” conveys a rear guard military action, thus God will be both before your face and at your back, prtecting your coming and your going, surrounding you. “When Israel busies itself with works of compassionate love, then it is like an army on the march, or a caravan, for which the righteousness that has become its own shows the way and makes a road, and which the glory of God (symbolized by the cloud and the pillar of fire in Exodus) protects and brings to its goal” (International Critical Commentary, page 362. Text in red my addition).
Isa 58:9 Then shalt thou call, and the Lord shall hear: thou shalt cry, and he shall say, Here I am. If thou wilt take away the chain out of the midst of thee, and cease to stretch out the finger, and to speak that which profiteth not.
Then shalt thou call, and the Lord shall hear: thou shalt cry and he shall say, Here I am. God has now given in the previous verses the answer to the people’s question in the first part of verse 3 where they asked, Why have we fasted, and thou hast not regarded: have we humbled our souls, and thou hast not taken notice?
If thou wilt take away the chain out of the midst of thee. These chains are the bands of wickedness with which they strapped the bundles of oppression and other burdens onto people (see verse 6).
And cease to stretch out the finger, and to speak that which profiteth not. According to St Jerome stretching out the finger was used as a sign of contempt or a threat. The reference to finger and speech calls to mind proverbs 6:12-13 which describes the acts of an apostate: A man that is an apostate, an unprofitable man, walketh with a perverse mouth, He winketh with the eyes, presseth with the foot, speaketh with the finger. (see also Isa 57:4)
Isa 58:10 When thou shalt pour out thy soul to the hungry, and shalt satisfy the afflicted soul, then shall thy light rise up in darkness, and thy darkness shall be as the noonday.
When thou shalt pour out thy soul to the hungry. The word translated here as soul has a broad range of meaning and is perhaps better translated as “life.” Many translations amend the text to read “When thou shalt pour out thy bread to the hungry,” but this means amending the actual text. It seems to me however that “life” can make good sense here; by sharing the basic necessities of life (such as bread) with the hungry you are pouring out your own life to them. To the ancients, sharing food was sharing life. Notice the close connection between laying down one’s life and sharing the basic necessities of life in 1 John 3:15-18~Whosoever hateth his brother is a murderer. And you know that no murderer hath eternal life abiding in himself. In this we have known the charity of God, because he hath laid down his life for us: and we ought to lay down our lives for the brethren. He that hath the substance of this world and shall see his brother in need and shall shut up his bowels from him: how doth the charity of God abide in him? My little children, let us not love in word nor in tongue, but in deed and in truth.
And shalt satisfy the afflicted soul. Recalls verse 5~Is this such a fast as I have chosen: for a man to afflict his soul for a day? What good does it do a man to voluntarily afflict his soul (life) with the devotion of fasting when those around him are afflicted with real hunger and he does nothing about it? And if a brother or sister be naked and want daily food: And one of you say to them: Go in peace, be ye warmed and filled; yet give them not those things that are necessary for the body, what shall it profit? (James 2:15-16).
Then shall thy light rise up in darkness, and thy darkness shall be as the noonday. Recall the words of verse 8 and the comments offered there. The word “then” indicates that what is being promised here will be an effect if one pours out his soul to the hungry and satisfies the afflicted soul.
Isa 58:11 And the Lord will give thee rest continually, and will fill thy soul with brightness, and deliver thy bones, and thou shalt be like a watered garden, and like a fountain of water whose waters shall not fail.
Once again see the comments on verse 8.
And the Lord will give thee rest continually. “And” would be better translated as “then,” for it continues the series of promised effects for helping the hungry and afflicted (see previous comment).
Like a watered garden. An image of God’s blessings (Jer 31:12). Like a fountain of water whose waters shall not fail. The one who pours out his soul (life, see verse 10 and notes there) as if it were water shall be abundantly blessed, and always remain a source of refreshment for those in need.