This is gathered from these words: unto love of the brethren.
Reason 1. Because hatred, envie, wrath, strife, enmities, and such like affections, especially, when they reflect upon the good, are some of those filthy pollutions of the flesh, from which the soule of the faithfull is purified, Galatians 5.19,20.
2. Because the purification of our soules makes us to love purity in others, and no man can take delight in the purity of others, unlesse he be in some measure purified himselfe.
3. Because in the mutuall love of the faithfull divers operations are exercised, to the performing whereof, their soules are in a speciall manner purified and sanctified, as doing good, bearing with infirmities, edification of the Church, and glorifying the name of the Lord.
Vse 1. This may serve to condemne those, that shew themselves great enemies to godly men: they may rightly be called Cainites, for they have gone in the way of Cain, with those to whom the woe is denounced by Iude, Verse 12.
2. To exhort us by all meanes to endeavour to gaine this brotherly love of the godly: wherein there is required, First, sincerity, that it should be without hypocrisie or simulation, so that it [♦]should not be in words or in shew, as the Apostle speaks, but in heart. Secondly, that it should be not only from the heart, but from a pure heart; because there is a kinde of love that is in some sort sincere, but yet it is impure, whiles that it doth either neglect the chiefest good or else useth such means to procure some good as are contrary thereunto: as if a man to deliver his brother from danger, should perswade him to deny the truth, or to dissemble. Thirdly, That it should be fervent, because the affection ought to be set in the highest degree upon those objects, where there is found to be the chiefest reason to stirre it up.
[♦] “shold” replaced with “should”
Doctrine 15. Regeneration, that is common to all the faithfull, is a strong argument to provoke them to love one another.
This is gathered from the end of verse 22. and the beginning of the 23. where this reason is given, why they should love one another, because they are borne againe.
Reason Because by this regeneration all the faithfull are brethren, begotten by the same Father, of the same blood, and partakers of the same spirit.