As I mentioned some time ago, the ESV Study Bible has a really bad entry on the Trinity, part of its appendix, “Biblical Doctrine: An Overview”. Today, I note that it repeats something I’ve often seen asserted elsewhere.
Perhaps the clearest picture of this distinction and union [of the Trinity] is Jesus’ baptism, where the Son is anointed for his public ministry by the Spirit, descending as a dove, with the Father declaring from heaven, “This is my beloved Son, with whom I am well pleased” (Matt. 3:13-17) All three persons of the Trinity are present, and each one is doing something different. (p. 2514a, emphases added)
This is an example of the sheer laziness and sloppy reasoning that so mars contemporary theology. Think about it - how exactly is the unity of the Trinity displayed here – either their oneness of an individual essence (godhead, divine nature) or the sharing of a universal property of deity? Where exactly do we see portrayed here the absolute equality of the three, or the “full divinity” of the Son and Spirit.
Would anything in this episode cause trouble for, say, an “Arian”? Nope. Tritheists? No – they should be OK with coordinated actions by the deities. Consider those unitarians who think the Holy Spirit is a force or divine action, not a person in his own right. They won’t have any problem with this “descending as a dove” – which of course needn’t mean that a literal dove (or something that looks just like a dove) dropped from the sky. Finally, consider modalists, who think that each person of the Trinity is really a personality of the one divine person, or a way that person acts. They’ll just say that this omnipotent, divine person can easily pull off these three actions simultaneously: getting baptized as a man, speaking from heaven, and coming down from heaven to empower the man.
The one sort of Christian theology that would trip on this, would be a strictly serial modalism – which holds that God acts, in sequence, as Father, Son, and Spirit, but only one at a time. But who holds this? (Apparently, not even these guys – see #56.)
In sum, this episode, spiritually inspiring and important to christology though it is, is nearly worthless when it comes to arguing for or just finding evidence for any particular understanding of the Trinity. Theologians should be more nervous about just repeating these tropes. A narrative which is compatible with almost any view of the Trinity neither implies, asserts, assumes, nor even illustrates “the” catholic/orthodox/historical mainstream view of the Trinity.

I strongly believe that the baptism scene in Mark and Luke help point to the trinity. And the following desert temptation scene clearly declares monotheism. So these two scenes kick out tritheism. And any Arianism that worships Jesus would get the boot.
Well, Matthew and Luke declare monotheism in the desert temptation scene.
Honestly, I think this picture is really hard to reason out as a human because a certain Being doing three acts simultaneously doesn’t make sense at all. But maybe, the explanation of the picture will distinguish the believers and the non-believers of God. I guess this event is so divine and we humans don’t have the right to question how this event took place because we are not holy. But I believe that every one of us wants to be protected. All of us want to be loved. And if we can’t find it in the hands of other people, there is nothing left but to believe in Someone who will never leave nor forsake us.
Hi shorter university,
Actually, unitarians, trinitarians, and other shades of theologians believe in an omniscient, omnipotent deity that can multitask much more than that. And perhaps I’m biased by my theological education, but I don’t see that as a hard thing to grasp.