As the fourth letter it represents the four voices of God: prophet, priest, king and judge. All the revelation of God in the OT came from the voices of these offices. The dalet is the full propositional word of God.
The meaning of the name is ‘poor‘ or ‘door‘. However, The metaphoric meaning is supported by pulling the lamed out of the middle. Dot דת means ‘law‘, ‘decree‘ or ‘commandment‘. The lamed in the middle says that the heart of the commandment is ‘teaching‘.
Paul says that the law has a shadow of the kingdom of heaven.
Heb 10:1 ¶ For the law having a shadow of good things to come, [and] not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect.
The purpose of the shadow is to speak of Christ. Jesus said that all the scriptures spoke of him.
When followed by a gimel in fish ‘dag’ דג means ‘commanded to pursue‘. Adam named the animals based on their behavior, and the darting fish looked like it’s commanded nature was to pursue.
Jesus fed people bread and fish. He said the bread represented his body on the cross. He also said that man does not live by bread/the cross, alone, but by every word that proceeds from the mouth of God. The fish represent the word of God which pursues man.
Jesus told Peter to feed his sheep after having eaten bread, and telling him to drag in 153 fish. Peter was commanded to feed them the cross and every word which proceeds from the mouth of God.