Ephesians 4:3

Endeavouring to keep the unity of the Spirit
That is, a spiritual union: there is an union between God and his people, and between Christ and his members, and between saints and saints, and the bond of each union is love; and that it is which knits and cements them together; and it is the last of these which is here intended: the saints are united under one head, and are members of one and the same body, and should be of the same mind and judgment, and of one accord, heart, and affection: and this may be called "the unity of the Spirit"; because it is an union of spirits, of the spirits or souls of men; and that in spiritual affairs, in the spiritual exercises of religion; and it is effected by the Spirit of God, by whom they are baptized into one body. Now to endeavour or study to keep and preserve this, supposes that this union does already exist; that it is very valuable, as making much for the glory of God, the mutual comfort and delight of saints, and is worth taking some pains about; and that it is very difficult to secure, there being so many things which frequently arise, and break in upon it, through the devices of Satan, and the corruptions of men's hearts: but though it is difficult, and may sometimes seem to be impossible, yet it becomes the saints to be diligent in the use of means to keep it up, and continue it; and which they may be said to endeavour after, when they abide with one another, and do not forsake each other upon every occasion; when they perform all offices of love to one another, and stir up each other to the like: and the way and manner in which this is to be kept, is

in the bond of peace:
the Arabic version reads, "by the bond of love and peace": by maintaining peace among themselves, and seeking those things which tend to, and make for peace, and spiritual edification; and which is called a bond, in allusion to the Greek word used, which comes from one that signifies to knit, join, and bind together, and because it is of a knitting and uniting nature. Now so to act is to walk worthy of calling grace, or agreeably to it: peace is what the saints are called unto in the effectual calling: and what is suitable to God, who is the God of peace; and to Christ, who is the Prince of peace; and to the Holy Spirit, whose fruit is peace; and to the Gospel, which is the Gospel of peace; and to the character which the saints bear, which is that of sons of peace.