When we eat, our bodies break down the food and get from it both energy and materials for building and repairing the body. The process is similar on a symbolic level in the Bible. Food represents the desire for good and the insight that comes from that desire for good – goodness and understanding that come from the Lord. But to put them to use we have to take them in and make them our own – which is spiritual eating.

4303. 'Therefore the children of Israel do not eat the sinew of that which was displaced, which is on the hollow of the thigh' means that no truths containing falsities were assimilated. This is clear from the meaning of 'eating' as being joined to and made one's own, dealt with in 2187, 2343, 3168, 3513, 3596, 3832, and from the meaning of 'the sinew' as truth, for truths within good are like sinews within the flesh, and truths are also meant in the spiritual sense by 'sinews' and good by 'flesh', 3579, 3813. 'Sinews' and 'flesh' have a similar meaning in Ezekiel,

Thus said the Lord Jehovih to these bones, I will lay sinews upon you and cover you with flesh, and I will put spirit within you I looked, and behold, there were sinews upon them, and flesh came up. Ezekiel 37:6, 8.

Here the new creation of man, that is, the regeneration of him, is the subject. But once truths have been distorted they cease to be truths any longer; and the more they are distorted into the reverse of truths the nearer they get to falsities. This is why 'the sinew of that which was displaced' means falsity. For 'the hollow of the thigh' means the point where conjugial love is joined to natural good, and therefore the point where the influx of spiritual truth into natural good takes place, see 4277, 4280. From this it is evident that 'therefore the children of Israel do not eat the sinew of that which was displaced, which is on the hollow of the thigh' means that no truths containing falsities were assimilated. The reason why these things are said concerning the children of Israel is that 'Israel' means the Divine celestial-spiritual, 4286, while 'children' or 'sons' means truths, 489, 491, 2623. So the meaning is that the truths belonging to the Divine celestial-spiritual did not assimilate any falsities as part of themselves.