'A trough,' as in Genesis 24:20, signifies the 'good of truth,' because the water in the trough signifies truth, and the trough itself has the same meaning as 'wood,' that is, good.

The good of truth is produced from good by truth. It is an offspring born of truth as a mother and good as a father. All genuine good in the natural self is from the marriage of good and truth in the rational.

This is what is called the good of truth, and is the meaning of 'trough' in the Word, as a place to receive water. 'A little trough,' as in Exodus 2:16, signifies the doctrine of charity. This because it is a wooden trough which holds water drawn from a well for flocks to drink. Anything wooden, in the internal sense, signifies the good of charity. 'To draw' signifies being instructed. 'The water' which is drawn signifies the truth of faith. 'The well' which it is drawn from signifies the Word. 'To give the flocks to drink' signifies instruction in good from the Word. This makes it clear that 'a little trough' denotes the doctrine of charity.

(Referenser: Arcana Coelestia 3095)

3095. 'And she hastened and emptied her pitcher into the trough' means the separation of the affection for truth which was being introduced into Divine good. This is clear from the meaning of 'emptying the pitcher' as separating truth (for 'a pitcher', being a containing vessel, means not only factual knowledge that has truth in it but also truth that has good in it, see 3068, 3079. In this instance truth that was being introduced into Divine good is meant, since introduction is the subject. And because truth itself is never joined to good except by means of its own affection, 3024, 3066 - for within the affection there is the life which enables them to be joined together - it is the affection for truth that is meant here); and also from the meaning of 'a trough' or channel to accommodate water, as truth which rests in good, for 'the water' in the trough means truth, 739, 2702, while the trough itself is similar in meaning to wood, namely good, 2784, 2812. Truth which rests in good is that which is produced from good by means of truth, and is like offspring born from truth as mother and from good as father. All genuine good in the natural man originates in this way, that is, from the marriage of good and truth in the rational. This good is that which is called truth that rests in good and is meant in the Word by 'a bough' or channel to accommodate water.