Isaiah 55 - Arthur Peake's Commentary on the Bible

The Glorious Blessings of the New Covenant which Yahweh will Make with His People. Yahweh bids the thirsty come to the waters, the hungry to eat. Their life is now a constant striving issuing only in disillusion; but listening to His call they shall, without effort or cost, enjoy the utmost blessing (fat or oil was considered a great delicacy). He will grant (as a condescension, not make as on equal terms) His people a covenant, transferring to them the sure promises of loving-kindness which He made to David. Even as once by crowning his career with success He made David an evidence to the nations of His power and their suzerain, Yahweh will now prosper Zion so that nations as yet unknown shall obey her call, seek union with her, beholding the wonderful blessings wherewith Yahweh honours her.

Seek Yahweh, for the Great Deliverance is at Hand. Let the exiles seek Yahweh, for the time is at hand. His plans for His people reach beyond their own as far as the heavens are exalted above the earth. Even as the rain and snow descend and do not return, but make the earth fruitful, so Yahweh's promise, that has gone forth from His lips, shall be accomplished without fail. (An utterance was looked upon by the Hebrews almost as a personal power fulfilling itself.) He will lead forth the rejoicing exiles, mountains and trees shall rejoice aloud as the happy procession passes. The thorn-bush and the brier (?) or nettle (?) shall give place to the fir and the myrtle, an everlasting memorial of Yahweh's gracious deliverance.