I had many things to write - This Epistle closes, as the second does, with a statement that he had many things to say, but that he preferred waiting until he should see him rather than put them on paper. Perhaps there were some things which he wished to say which he would not like to have exposed to the possibility of being seen by the public eye.
But I will not with ink and pen - Notes at 2-John 1:12.

I had many things to write - That is, I have many things that I might write; but having the hope of seeing thee shortly, I will not commit them to paper. Ink and pen are here mentioned; paper and ink in the preceding epistle.

I have many things to write,.... With regard to churches, and particular persons, and concerning hospitality to the poor brethren:
but I will not with ink and pen write unto thee; suggesting he should take another method of communicating his mind to him, which he next mentions.

Here is the character of Demetrius. A name in the gospel, or a good report in the churches, is better than worldly honour. Few are well spoken of by all; and sometimes it is ill to be so. Happy those whose spirit and conduct commend them before God and men. We must be ready to bear our testimony to them; and it is well when those who commend, can appeal to the consciences of such as know most of those who are commended. A personal conversation together often spares time and trouble, and mistakes which rise from letters; and good Christians may well be glad to see one another. The blessing is, Peace be to you; all happiness attend you. Those may well salute and greet one another on earth, who hope to live together in heaven. By associating with and copying the example of such Christians, we shall have peace within, and live at peace with the brethren; our communications with the Lord's people on earth will be pleasing, and we shall be numbered with them in glory everlasting.

I will not--rather as Greek, "I wish not . . . to write" more.

I had many things to write. These verses correspond with 2-John 1:12-13.
The friends. An uncommon title in the New Testament, where it is almost supplanted by the dearer title of "brethren" or the holier one of "saints."