From The Gospel of Mark, by Mary Healy, commenting on Mark 1:29-39
Given the stunning displays of power just recounted, there is a note of simplicity and humility in the report that Jesus rose early to go off and pray. Although he speaks and acts with divine authority, Jesus seeks guidance from God like an ordinary man.
Both the time and the place chosen by him are especially suited to prayer. Mark emphasizes the early hour, very early before dawn, as if, like the psalmist, Jesus desires to precede the sunrise in giving glory to God: “Awake, my soul; awake, lyre and harp! I will wake the dawn” (Ps 57:9; see 88:14; 92:2). The deserted place recalls the desert in 1:3–13, a place of solitude conducive to intimate communion with God. Aware that crowds will always be flocking to him from this point on, Jesus is determined to find the time he needs to renew his communion with the Father in prayer (see Mark 6:46; 14:32–42).
Simon Peter acts on behalf of the many who are looking for Jesus because they perceive in him the answer to their deepest longings. Jesus had taken the initiative in calling the disciples (1:16–20), but now they pursue him, or “track him down.” There may be an allusion here to the bride’s pursuit of her beloved in the Song of Songs, interpreted by the ancient Jews as an image for Israel’s spousal love for God: “in the streets and crossings I will seek him whom my heart loves. I sought him but I did not find him” (Song 3:2–4). In a real sense, “everyone is looking for” Jesus, whether they know it or not.
Upon their “finding him,” Jesus replies with a solemn declaration of the purpose of his mission (see John 18:37 for a similar declaration). Have I come suggests more than Jesus’ appearance in public; it alludes to his being sent into the world by the Father, and thus implies his preexistence (see Mark 9:37). He has come to preach, that is, proclaim the kingdom (1:14), on an increasingly wider scale. And his preaching, as is evident from the episodes already narrated (1:15–34), consists not merely of words but of a power that has a dramatic impact on his listeners, making the kingdom a reality in their lives. By saying “let us go” Jesus includes his disciples in that mission. His time alone with his Father has confirmed him in his self-understanding and prepared him for the whirlwind of ministry to follow.