Joshua's is a shocking refusal. "You cannot serve Yahweh, for he is a holy God; he is a jealous God; he will not go on forgiving your rebellion and your sins." If you desert him, he will consume you. Don't lightly mouth your profession of faith, Joshua is saying. Don't you realise the sort of God you are dealing with? He is a holy, jealous God. You didn't dare come to him thinking, "though it makes him sad to see the way we live, he'll always say, 'I forgive.'" Yahweh is not a soft, cuddly Santa in the sky who drools over easy decisions during invitation hymns. Joshua seeks to put down that blathering self-confidence that makes emotional commitments rather than shutting its mouth and counting the cost.
"You cannot serve Yahweh." Neither Israel nor the church could hear a more beneficial word than that.
It was precisely when the Jesus bandwagon was going great guns (Luke 14:25) that Jesus emphasized who "cannot be my disciple." Rather, one must carefully "count the cost" before yielding allegiance to Jesus. The church should note this. Too frequently, the Jesus we present is some variety of prepackaged joy, peace and provision that works twice as fast as aspirin. He is our cellophane Christ. We should not sell Christ like that but warn people about him! Our task is not to bait people into saying, "I will lay down my life for you" (John 13:37), but to get them (and ourselves) to squirm under his searching, "Do you love me?" (John 21: 15-19). Too many of us perjure ourselves before a holy Judge as we sing, "I surrender all," or "My Jesus, I love thee." There are stanzas in some hymns that I dare not sing.
One of the healthiest things a Christian can do is to doubt and question his easy expressions of commitment. One of the ordination vows my denomination asks of me is:
Do you engage to be faithful and diligent in the exercise of all your duties as a Christian and a minister of the Gospel, whether personal or relational, private or public, and to endeavour by the grace of God to adorn the profession of the Gospel in your manner of life, and to walk with exemplary piety before the flock of which God shall make you overseer?I would not touch that with the proverbial ten-foot pole. It asks too much of a proud, angry, lustful, covetous man. I affirm it only because there is that clause, "by the grace of God," in it. Otherwise, I would have to turn away, for it would be too much to promise. Baptismal, membership and marriage vows should receive the same scrutiny.
Dale Ralph Davis in No Falling Words, expositions on the Book of Joshua, pages 201-2