Isaiah 63:10

Even though the Israelites pledged themselves to follow the Lord faithfully, they rebelled against Him and so grieved His Holy Spirit. This verse helps us understand what grieving the Holy Spirit involves, namely, rebelling against the Lord (cf. Ephesians 4:30). This verse, the next, and Psalms 51:11 are the only places in the Old Testament where "holy" describes God’s "Spirit." We offend the holiness of God when we rebel against Him. Of course, we also offend His love since we "grieve" or "hurt" Him. Holy behavior is impossible without a will that is compliant rather than rebellious toward God.

"Most commentators recognize that the understanding of the Holy Spirit here and in Isaiah 63:11 is close to the fully developed NT concept of the third person of the Trinity. Here he is clearly a person who is capable of being hurt by human behavior, and in Isaiah 63:11 he is the empowering and enabling presence in the human spirit. As Delitzsch says, ’He is the Spirit who is both holy in himself and capable of producing holiness.’ In Isaiah 63:12, although the adjective ’holy’ is not used, the same Spirit is the one who guides and provides for the people of God." [Note: Oswalt, The Book . . . 40-66, pp. 607-8.]

However, these verses make perfectly good sense if we read "holy spirit" in place of "Holy Spirit." Yahweh, the angel of His presence, and the Holy Spirit are distinguishable as three persons of the Trinity.

The Israelites’ rebellion led God to oppose them by fighting against them, resisting them. It was not God who changed but His people. He consistently resists sin.