"Be devoted to one another in brotherly love; give preference to one another in honor; not lagging behind in diligence, fervent in spirit, serving the Lord..." Rom 12:10-11 NAS
This month I posted an article on Genesis 6:4-7 which discusses events before the Great Flood ("Who are the “Sons of God” in Genesis 6:4-7?" or "谁是创世记6：4-7中的“神的儿子”？). My arguement is that the story about the "sons of God" and the "daughters of men" is not a mythological account of angels mating with women right before the Flood as even some evangelicals believe, but a metaphor of what happens when people of God over time discard their faith and lose everything. Genesis 6:4-7 is discussed in terms of believers and unbelievers intermingling through intermarriage.
There is much in the Bible about diligence. For example, Ezra saw great progress in the building of the temple due to the diligence of the people (Ezra 5:8). The writer of Hebrews promised realization of their dreams due to the people's diligence. Persistence and diligence will more often than not lead to good things.
Paul tells Timothy that in the later times some will abandon their faith and follow deceiving spirits (1 Timothy 4:1). They will ignore sound doctrine and embrace things taught by demons. This sounds much like what happened on the earth before the Great Flood. The apostasy didn't happen over night but over a long period of time. Paul tells followers to embrace diligence in the practice of their faith: "Until I come, devote yourself to the public reading of Scripture, to preaching and to teaching...Be diligent in these matters (1 Timothy 4:13-15). We must not repeat the disgrace of abandoning faith in God as was done before the Great Flood.
Pray: "Dear God, make us combatants in God's army, in diligence contending for the faith"