Jesus referred to a baptism that he was desiring. He employs passive language, so it’s something he undergoes or receives, not something he administers. He is obviously not referring to his water baptism, as that was in the past. I’ve long understood this as a reference to the suffering on the cross, as undergoing the judgment of God. Baptism has allusions to judgment as a passing through waters, death and renewal. Though the early church tradition understood martyrdom as a baptism of sorts in blood, I don’t think Jesus specifically has the idea of being covered in blood in mind, though there’s nothing to preclude one from treasuring the theological implications of such. D.L. Block succinctly summarizes 3 common views as follows:
- 1. One option is that it refers to Christian martyrdom or a baptism of blood (BAGD 132 §3c; BAA 266 §3c; such a view is present from the time of Irenaeus according to Oepke, TDNT 1:538 n. 44). But a general reference to martyrdom is too broad for this context (Bayer 1986: 79). In addition, the conceptual parallel in Mark 10 says that only Jesus can experience this baptism.
- 2. It may be an allusion either to John’s baptism or to Christian baptism, which is the normal meaning of the term. However, this context refers to an act of humiliation, which is not the picture given by either of these baptisms. Both John’s baptism and Christian baptism are rites that one partakes in, but this baptism is something thrust upon Jesus (βαπτισθῆναι, baptisthēnai, is passive). In addition, the disciple’s inability to experience this baptism in the parallel Mark 10:38–39 makes no sense if the rite is the focus (Bayer 1986: 79). John’s baptism cannot be meant, since Jesus already had it (Fitzmyer 1985: 997). That this baptism is not in view argues against the church’s creating this saying.
- 3. The best view argues for a figure depicting the “inundation of the waters of divine judgment” (Creed 1930: 178; Plummer 1896: 334; Oepke, TDNT 1:535–36; Job 9:31 [uses βάπτω, baptō, to dip]; cf. 9:28, 32, 35). The imagery of floods for persecution or judgment is common in the OT (Ps. 18:4, 16 [18:5, 17 MT]; 42:7 [42:8 MT]; 69:1–2 [69:2–3 MT]; Isa. 8:7–8; 30:27–28; Jon. 2:3–6 [2:4–7 MT]; Bayer 1986: 81).
 Bock, D. L. (1996). Luke Volume 2: 9:51–24:53. Baker Exegetical Commentary on the New Testament (1193–1194). Grand Rapids, MI: Baker Academic.
© 2012, Rick Hogaboam. All rights reserved.