The verb achaz means to grasp, seize, take hold of, or clutch. It conveys the decisive action of laying hands on something and holding on. It appears in contexts of physical grasping, the holding of weapons, the clenching of fear (trembling and seizing), and most significantly the spiritual posture of clinging to God's wisdom and promises.
In Genesis 25:26, achaz captures the moment Jacob was born grasping Esau's heel — a detail that foreshadows his entire life of wrestling with God and man until he receives the blessing. Proverbs 3:18 calls wisdom 'a tree of life to those who lay hold [achaz] of her', urging believers to seize divine wisdom with the same tenacity. The opposite of achaz is letting go — releasing what God has promised or releasing obedience to His commands. Isaiah 56:4 uses achaz for 'holding fast to my covenant', an image of covenant loyalty as a white-knuckled grip on God's word. For the warrior-disciple, achaz is both sword-hand and faith-hand: you hold your weapon and you hold your God.