There is a Christian story in the Bible in which Jesus is being tempted by Satan/the devil. He responds by saying, "Get thee behind me Satan!" which is a rebuke or refusal of temptation - a sort of way of saying, "NO!" to the devil's temptations. MY INTERPRETATION OF THE MEANING HERE: In this passage, I would say that the father is acknowledging the "evils" of drinking and also acknowledging his "friendship" with alcohol. Instead of saying, "Get thee behind me" to rebuke the devil, he is saying, "Get thee behind me AND PUSH" (Get behind me, my "friend", and help me get through this).