11. Why was it so timely for the Chief Shepherd to warn the congregations of developing trends?

¹¹ Nevertheless, the apostle Paul had foretold that there would be an apostasy among the anointed Christians, and Jesus’ messages show that in John’s old age this apostasy was already developing. John was the last of those who acted as a restraint on this all-out attempt by Satan to corrupt the seed of the woman. (2 Thessalonians 2:3-12; 2 Peter 2:1-3; 2 John 7-11) So it was the appropriate time for Jehovah’s Chief Shepherd to write to the elders in the congregations, warning of developing trends and encouraging righthearted ones to stand firm for righteousness.

Indeed, the clergy of Christendom have been the most prominent members of Satan’s seed. Speaking of these as ‘the lawless one,’ the apostle Paul foretold that their “presence is according to the operation of Satan with every powerful work and lying signs and portents and with every unrighteous deception.”​—2 Thessalonians 2:9, 10.

16. (a) Against whom did Christendom’s leaders show special hatred? (b) What took place in Christendom during the Middle Ages? (c) Did the Protestant rebellion, or Reformation, change Christendom’s apostate ways?

¹⁶ While claiming to be shepherds of the flock of God, Christendom’s leaders, religious and secular, showed special hatred for anyone who tried to encourage Bible reading or anyone who exposed their unscriptural practices. John Hus and Bible translator William Tyndale were persecuted and martyred. During the bedarkened Middle Ages, apostate rule reached a peak in the diabolic Catholic Inquisition. Any who disputed the teachings or authority of the church were unmercifully suppressed, and countless thousands of so-called heretics were tortured to death or burned at the stake. Thus Satan endeavored to ensure that any true seed of God’s womanlike organization would be quickly crushed. When the Protestant rebellion, or Reformation, occurred (from 1517 onward), many Protestant churches manifested a similar intolerant spirit. They too became bloodguilty by martyring those who endeavored to be loyal to God and Christ. Truly, “the blood of holy ones” was freely poured out!​—Revelation 16:6; compare Matthew 23:33-36.