How do we know God is patient and merciful?

The Apostle Peter in 2 Peter 3:9 explains that 'The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish, but that all should come to repentance.' This highlights God's mercy as He endures the opprobrium of a sinful world, waiting for His people to turn to Him. His willingness to wait for sinners to repent underscores His deep love and commitment to salvation, exemplifying His character as patient and merciful.