The Greek verb makrothumeō (from makros, long + thumos, passion/temper) means to be long-tempered — to hold back the natural impulse to react, punish, or give up. It is the verbal form of makrothumia (G3115). It appears in Hebrews 6:15 (Abraham 'patiently endured'), James 5:7–8 (the farmer waits patiently for rain; you too be patient), Luke 18:7 (God will bring justice for his elect — will he delay?), and Matthew 18:26 (the servant begs: 'be patient with me').
Makrothumeō is one of the most Christ-like virtues. In 1 Corinthians 13:4, love 'makrothumei' — it is long-tempered, it does not snap back or give up quickly. James 5:7–8 uses the farmer's patient waiting for harvest rain as the model for the believer's waiting for the Lord's coming — patient not because nothing is happening but because something certain is coming. God himself is the supreme model: 2 Peter 3:9 says God is not slow to fulfill His promise but is makrothumōn — patiently holding back judgment so that all might come to repentance.