Mat 10:7 And as you go, preach, saying, The kingdom of heaven is at hand.

The word translated as "preach" is kerusso, which means "to act as a herald," "to proclaim," and "to declare."

We have already written extensively about the meaning of "the kingdom of heaven" (basileia (reign, rule, or kingdom) ouranos (heavens, sky, universe).

The word translated as "at hand" is eggizo (engizo), which means "to bring near," "to approach," "to bring up to," and "to be imminent."

So Christ isn't telling the apostles (or us) to preach in the traditional sense. He is simply teaching us to be heralds for the new age, the imminent age where the universal rule comes into its own.