Romans 12:15

Rejoice with them that do rejoice
Not in anything sinful and criminal, in a thing of nought, in men's own boastings; all such rejoicing is evil, and not to be joined in; but in things good and laudable, as in outward prosperity; and to rejoice with such, is a very difficult task; for unless persons have a near concern in the prosperity of others, they are very apt to envy it, or to murmur and repine, that they are not in equal, or superior circumstances; and also in things spiritual, with such who rejoice in the discoveries of God's love to their souls, in the views of interest in Christ, and of peace, pardon, and righteousness by him, and in hope of the glory of God; when such souls make their boast in the Lord, the humble hearing thereof will be glad, and will, as they ought to do, join with them in magnifying the Lord, and will exalt his name together:

and weep with them that weep;
so Christ, as he rejoiced with them that rejoiced, at the marriage in Cana of Galilee, wept with them that wept, with Mary at the grave of Lazarus. The design of these rules is to excite and encourage sympathy in the saints with each other, in all conditions inward and outward, and with respect to things temporal and spiritual; in imitation of Christ their great high priest, who cannot but be touched with the infirmities of his people; and as founded upon, and arising from, their relation to each other, as members of the same body; see ( 1 Corinthians 12:26 ) ;