The altar rail separates the congregation from the Sanctuary, symbolising our sin, separating us from Heaven and from God. The holy place is on that side, and we’re stuck on this side, able to look but not enter.
But the altar rail also stands for Christ Himself, who for our sake became sin. As the altar rail stands in the middle, as both sanctuary and nave, and the meeting point between them, so Christ, in becoming our sin, has made it the meeting point of heaven and earth.
And it’s at this meeting point that we come, right to the threshold of Heaven, to kneel down, receive God Himself into us, and take Him out into the world.
God bless you!