When God promised the people of Israel that he would never leave them, they took God at his word.
When Jesus promised his followers I am with you always, they took him at his word.
But the people of Israel watched the temple, the place where God lived, burn to the ground. And the disciples watched Jesus ascend to Heaven.
But God came back. In tongues of fire, and in the rushing wind, God moved back in with his people.
Setting up residence in temples made of flesh and bone, and with the intimacy of walking with Jesus, the Holy Spirit means God is with his people for all times and in all places.