What does 'but thou remainest' mean in Hebrews?

The phrase 'but thou remainest' from Hebrews 1:11 serves as a powerful reminder of God's eternal nature. It highlights the contrast between the created world, which is subject to decay and change, and God, who remains unchanged and eternal. This concept is vital for believers, as it affirms that while everything around them may fluctuate, God's presence, love, and promises will never wane. This assurance encourages Christians to cultivate their relationship with the eternal God and find solace in His permanence amidst life's trials.