This chapter is a bit “jumpy” – moving from one thought to another. Sounds like me.
First part talks about the Lord, how he brought vengeance, redemption. His clothes red with blood. This is no slap in the wrist. Verse 5 speaks to me, stirs something in me. Probably because of how God wired me, I understand this, “I looked, but there was no one to help; I was appalled, but there was no one to uphold; so my own arm brought me salvation, and my wrath upheld me.” (Isaiah 63:5 ESV)
Isaiah remembers the love, goodness, compassion of God. Then he remembers how we rebel and grieve the Holy Spirit. Then how God has shown his power and strength. Then asks for mercy, for God to come and bring His kingdom. Then remembers again how unworthy, unclean, we are before a holy, immortal, all powerful God. Then makes another plea for compassion.
I think this is what it means to worship in spirit and in truth. This is true prayer.