Isaiah 7:13
Then Isaiah said, "Hear now, you house of David! Is it not enough to try the patience of men? Will you try the patience of my God also?

To try the patience of man is not uncommon. Daily I try the patience of my wife by being selfish and demanding. I try the patience of my kids by being too firm or too busy. I try the patience of my coworkers by being self-centered and dismissive.
If it's this easy to try the patience of man, how much more often do I try the patience of a perfect, holy and just God? My family, friends and acquaintances can be offended only my my words and actions. God takes offense to my thoughts, my motives, my attitudes and the condition of my heart. And somehow I still maintain (and try to convince those I'm offending) that God favors me. While God does favor and has favored me in both eternal and temporal ways (Eph. 1:11), daily He is patient with me. Daily He is merciful and forgiving. God's stance of favor with me in solely based on the magnitude of His virtue and holiness, not my worthiness.
Therefore, when I approached the throne of God in prayer, or interact with others, I must remind myself of the patience and mercy of God. This thought should drive me to both change my behavior and words as well as humble my thoughts and motives.

2 Peter 3:9
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.

Father I praise You for being patient and merciful. Teach me to be like You and act like You day by day, moment by moment. Amen.