Dear Dr. Luginbill, Could you help me with an interpretation problem in the OT? It's Isaiah 63:10-15. It says that Israel "grieved the Holy Spirit", but who is the HE in "therefore, He turned Himself to become their enemy..." Is it God the Father that is being spoken of, or still the Holy Spirit? It's hard to tell. And aren't these verses someplace in the NT, and attributed to the HS? I know the latter part of Ps. 95 is attributed to the HS in the NT, but it is YHWH speaking in the OT. Just wondering. Thanks again for your help. I don't know whom else to ask. God bless you.
Glad to help. As far as I am aware, these verses aren't directly quoted in the NT, but for NT allusions to this passage, consider Acts 7:51; Eph.4:30; Heb.13:20.
Isaiah 63:10ff. is one of the great Old Testament "Trinitarian" passages, because it is difficult to read these verses in any other light than that the Trinity was revealed in the Old Testament as well as in the New (just not always as obvious as in the NT). After all, who could the Messiah be except God? And the Spirit of God too is evident from the first verses of the Bible (Gen.1:2), with the Trinity saying in unison later in that first chapter of Genesis "Let us make man in Our image" (Gen.1:26). Here in Isaiah chapter 63, we have all three members of the Trinity at work in their superintendence of Israel in the desert. "They grieved His [the Father's] Spirit" (v.10), whom "He [the Father] had set among them, who [also] sent His Glorious Arm [Jesus Christ] of power to be at Moses' right hand" (v.12; cf. Is.53:1 "to whom has the Arm of the Lord been revealed"). In fact, whenever God appears in the Old Testament, He is doing so through the Person of His Son, to whom He has delegated the entire role of dealing directly with mankind, most notably in His two advents, the first to redeem us through His blood, the second to deliver His people through His power (cf. Heb.1:1-3). Isaiah himself, in chapter six, sees "God", but we find out in John's gospel that this too is a Christophany, that is, an appearance of our Lord as the Father's representative (John 12:41). Jesus is the only way to the Father (Jn.14:6), and the Trinity have taken pains to give a consistent picture of this critical fact throughout the Bible. There is much more about the issue of Theophany and Christophany in "Bible Basics: Essential Doctrines of the Bible in Outline: Part 1: Theology".
To answer the other specifics of your question, the "His" in the phrase "His Spirit" here in Is.63:10 refers to the Father, but it is well also to remember Christ's words, "I and the Father are One" (Jn.10:30), and the Spirit is often also associated with Christ in the NT (cf. Acts 16:6-10; Rom.8:9-11; 2Cor.3.16-17). Simply put, the Trinity are "one" in a way that mankind can not really comprehend, and are never, never "at odds" about anything in any way (it would be impossible for them to be anything but completely unified in all they think, say and do).
Psalm 95, the last passage you mention, is a perfect example of what we are talking about, because it is true that the LORD is the One to whom these words are attributed in the Psalm, the "Rock" of verse one. Yet in the New Testament, Paul has no trouble attributing this Psalm to the Holy Spirit. And who, after all, is our Rock, if not our Lord and Savior Jesus Christ (Matt.7:24-25; 16:18; Rom.9:33; *1Cor.10:4; 1Pet.2:6-8)? Who really was it who led the Israelites through the desert and appeared in the pillar of cloud and fire, if not the Messiah Himself, the Angel of His Presence (cf. Is.63:9)?
It is an imperfect analogy at best, but most human actions are conceived as thought, expressed by word, and done by hand. If we think of the Father as the One who authorizes the plan, the Son as the One who carries out the plan, and the Spirit as the One who communicates the plan, we shall have at least an inkling of the fact that the Trinity have agreed upon distinct roles for carrying out the awesome Plan of God, even though these roles of necessity interlock and are intimately part and parcel of the same thing (as a thought-word-deed is as well). Because the coming of the Messiah as God and Man in One Person was of necessity imperfectly understood before Jesus' first advent, the distinction between Father as authority for the plan and Son as administrator of the plan was also imperfectly understood, although we now understand after seeing Jesus in the flesh and beholding His blessed work for us on the cross (and with the help of many New Testament passages explaining these things), that it has always been the Son who has been the Arm of the Lord rendering salvation, from His creation and restoration of the world at the Father's behest, to the rendering of salvation through His sacrifice, to His return and subduing of all God's enemies in that coming time (cf. Heb.1:1-13).
It still may be that we see some of things now with less clarity than we would like, "through a glass and darkly" as it were, but the day is coming soon when we shall see our Master face to face, and "shall know even as we are known" (1Cor.13:12). Until that blessed day, scripture has given us more than enough information to say with certainty that the Trinity are clearly visible throughout the Bible, and that the parts they have chosen to play in God's gracious redemption of mankind are clear as well, being most visible and perspicuous in the Person of our Lord Jesus Christ, in the person, appearance, and face of Him in whom we see the actual Glory of God (2Cor.4:6), for all who have seen Him have indeed seen the Father (Jn.14:8-14).
You may also get some help from the following links:
The Persons of God: The Trinity (in Bible Basics Part 1: Theology)
The One True God and the Trinity in the Old Testament
The Trinity et al.
Explaining and Defending the Trinity
The Trinity in Scripture.
Questioning the Trinity
In anticipation of that wondrous day when we behold our Lord face to face,