The character of God can be best understood when looking at his love, affection and faithfulness to His Church. The OT traces a story-line of how God sets apart a people or a church for himself, of how he shows his faithfulness by constantly guiding them along in mercy and love.
Isaiah 27 is an assurance from God that he will keep His promise to Israel. That he will re-establish His Church. I will watch over the fruitful vineyard, He says in verse 3 and declares that Jacob will take root in verse 6. He even prompts the people to look in retrospect to prove his faithfulness to his church in in verse 7.
Chapter 28 in Isaiah shows that even with God loving his Church or Israel the way he did, they constantly gave in to their sinful desires. We, his beloved are sinners and have been born into iniquity. However there is a truth mentioned in verse 5 of chapter 28 that in the face of the sin of the leaders of Ephraim and Judah the Lord Almighty will be a glorious crown and a beautiful wreath for the remnant of his people. He will be their source of strength and he will be their righteousness.
Our churches today are not perfect, we are broken and sinful and are inclined to the ways of the leaders of Ephraim and Judah. But it is here, in our brokenness that he will be our glorious crown, it is here that the cross of Christ will be our source of strength and righteousness. We see this clearly in Acts 21 where the church, although sinful works as a unit to carry the love of Christ. This is seen in the way they welcome Paul on this journey.
Let us also, knowing our brokenness, be ever so filled with the knowledge of his love that it overflows from us to the people and the world around us.