The account of the baptism moves immediately into Jesus’ test in the wilderness (eremos) as seen in the phrase “At once.” Jesus’ expulsion into the desert is the necessary consequence of his baptism; it is the same Spirit who descended upon Jesus at his baptism who now forces him to enter more deeply into the wilderness. In Mark, the Spirit is “casting out” or “throwing out” (ekballo) Jesus into the wilderness. (Matthew and Luke are a bit less graphic with the Spirit “leading” [anago & ago] Jesus.) In the wilderness Jesus is to be tested (peirazo) by Satan (Mk) or the Devil (Mt & Lk).
In comparison with other gospel writers, Mark appears to have preserved no more than a hint of the tradition. It is essential to view the account in Mark’s perspective. These brief verses describe what it means for Jesus to heed John’s summons to the wilderness; the several details are subservient to this description. The evangelist seizes upon the fact that the Lord, who was announced and baptized in the wilderness, continues there for forty days. Even though God has declared Jesus as the beloved Son, the mission is only beginning for the One who is like us in all things except sin. As we are tested, so too is Jesus: the Spirit does not allow him to abandon the wilderness after his baptism.
As Pheme Perkins  notes:
“Unlike Matthew and Luke (Matt 4:1–11; Luke 4:1–13), Mark does not explain how Satan tested Jesus in the wilderness. The stories of Israel in the wilderness and of Adam and Eve in the garden provide examples of what it means to be tested and fail. One frequent element in these stories is the lack of confidence in the Word of the Lord. Even though they have been delivered from Pharaoh’s army, the Israelites think that God might leave them to die in the wilderness (Exod 16:2–3). Even though they can see God’s presence on Mt. Sinai in thunder, cloud, and trumpet blast (Exod 19:16–20; 24:15–18), the people think that Moses has perished and persuade Aaron to make them a calf idol (Exod 32:1–6). Jesus, on the other hand, remains faithful to God. In return, the wild animals are peaceful, and angels provide nurture for him.”
Jesus obeys the prompting of the Spirit’ v.13 clarifies the consequences of Jesus’ obedience – confrontation by Satan and temptation, exposure to the wild beasts, and reception of the ministry of the angels.
Temptation. All the gospel accounts use the word peirazo. Translators have to decide if the word means “to test” or “to tempt”. It has both meanings. In a “test” the tester is not trying to fail people, but to determine what they know or to let the one being tested discover what they truly know. In a “temptation” the tempter is hoping for failure.
The word is often used in the LXX of God testing people:
- God tested Abraham by asking him to sacrifice his son (Gen 22:1).
- When God rained bread from heaven, God asked that they gather only enough for that day. “In that way I will test them, whether they will follow my instruction or not” (Ex 16:4).
- A purpose of God’s testing is given in Dt 13:3b: “for the LORD your God is testing you, to know whether you indeed love the LORD your God with all your heart and soul”
A closely related word, ekpeirazo, is used in Dt 8:2: “Remember the long way that the LORD your God has led you these forty years in the wilderness (eremos – same word in temptation stories), in order to humble you, testing you to know what was in your heart, whether or not you would keep his commandments.”
Temptation is the predictable fact of remaining in the wilderness. This pattern is frequently associated with the wilderness tradition in both the OT and NT. The fact that Jesus is tempted by Satan, who attempts to frustrate the work of God, serves to emphasize the radical character of the issue. Jesus’ residence in the wilderness, inevitably results in a clash with the adversary of God. In this connection the cosmic language of Mk. 1:9–12 is important; it indicates that what happens on the plane of human decision in terms of John’s call and Jesus’ response is an aspect of the struggle between God and Satan.
Mark 1:12 drove. This is strong language. The Spirit compelled Jesus to go to the wilderness, where he encountered Satan; the encounter was not accidental. The text is better translated “casting out” or “throwing out” (ekballo) Jesus into the wilderness. (Matthew and Luke are a bit less graphic with the Spirit “leading” [anago & ago] Jesus.)