From The Gospel of Mark by Mary Healy, commenting on Mark 6:34:
The hoped-for retreat has been sabotaged. But instead of reacting with exasperation Jesus is moved with pity at the sight of the needy crowds. This is one of the few occasions where Mark gives us a glimpse into the emotions of Jesus, here using a verb that connotes a deeply felt, gut reaction (see 1:41; 8:2). Pity, or compassion, is one of the most distinctive attributes of God (Ps 86:15; Isa 54:78; Hosea 11:8). Jesus recognizes that the people are like sheep without a shepherd, a phrase often used to describe the condition of God’s people in the absence of sound leadership. As shepherdless sheep are likely to scatter, get lost, and quickly become vulnerable to predatory beasts, so when leadership fails, God’s people are likely to stray away from fidelity to him and become prey to their enemies. After Israel had experienced centuries of incompetent, self-seeking, and corrupt leadership (as exemplified by Herod Antipas), there was a growing recognition that ultimately only God himself can adequately guide his people and provide for their needs. The prophets had announced a great promise: “Thus says the Lord God: I myself will look after and tend my sheep. . . . I myself will pasture my sheep; I myself will give them rest” (Ezek 34:11, 15; see Isa 40:11; Jer 31:10). Mark hints that Jesus himself is the divine Shepherd (see John 10:118), the fulfillment of God’s promise to care for his people directly and no longer through an intermediary.