Full context is necessary to understand the passage, 2 Peter 3:9:
1 Dear friends, this is now my second letter to you. I have written both of them as reminders to stimulate you to wholesome thinking.
2 I want you to recall the words spoken in the past by the holy prophets and the command given by our Lord and Savior through your apostles.
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8 But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day.
9 The Lord is not slow in keeping his promise, as some understand slowness. He is patient with you, not wanting anyone to perish, but everyone to come to repentance.
Who is the Lord patient with?
You.
Who are the "you" being spoken to in the above? :AMR: