The attitude and behaviour of the enemy is described here. Their heart is without feeling; they have no pity. They speak haughtily. What lives in their hearts comes out in words. They are cold and insensitive. Words from the prophets do not enter their hearts. Their heart is unfeeling like fat
(Psalm 119:70) and because of that they are not open for warnings. Think of the heavy task given to Isaiah, in Isaiah 6:9–10, where he is asked to address the people with these words: Keep on hearing, but do not understand; keep on seeing, but do not perceive. Make the heart of this people dull, and their ears heavy, and blind their eyes; lest they see with their eyes, and hear with their ears, and understand with their hearts, and turn and be healed.
God’s words through the prophet collide with deafness and blindness. So, they are not open for God’s words.
Directed by their hearts, they utter threatening language. Then it turns into action. They surround us, wherever we go. Escaping is impossible. They spy on us to overpower us. Comparing with Psalm 10:10, we may also consider another translation: they surround our steps; they spy on us, and bow (themselves) to the ground. The bowing to the ground is then the opponent’s tactic; just like a predator, making itself very small before attacking its prey. In the first translation it is about the result of the spying, namely that the victim loses, and falls to the ground.
In Psalm 17:12 the attacker is described as a lion, which is eager to devour its prey; like a young lion, hidden in the bush. You do not really see the attacker, but something is amiss even though you do not quite know where danger is lurking.
The change from singular in Psalm 17:8 to plural in Psalm 17:11 happens more often; it is a regularly used variation which has no significant meaning.
10 They close their hearts to pity; with their mouths they speak arrogantly.