1:13 The children of thy elect sister. It is usually supposed that this refers to a sister in the flesh, also one of the elect, whose children, probably grown up and Christians, were at that time with John.
1:13 The children of thy elect or Christian sister - Absent, if not dead, when the apostle wrote this.
1:12,13 The apostle refers many things to a personal meeting. Pen and ink were means of strengthening and comforting others; but to see each other is more so. The communion of saints should be maintained by all methods; and should tend to mutual joy. In communion with them we find much of our present joy, and look forward to happiness for ever.