In the process of sanctification – which is ‘working out your salvation’ – there are two applications of the one tool.  The two applications are petition and promise.  The one tool is prayer.

Both applications reflect the same apprehension of the relationship between the one praying and the One to whom the prayer is offered.  That relationship is one of dependence and trust, of trustful dependence.  In petition, the apprehension of that relationship is apparent; but it’s no less so in promise: the two are in fact symmetric.

When we petition for something, we are sealing our acknowledgement that the provision is from God and not from anywhere else, and especially not from us or our merit.  We are apprehending grace.

When we promise, we are equally apprehending grace, although here it’s in the context of surrendering something of ourselves, trusting to receive something better.  What we are surrendering is something that we, as we are, experience as of value.  We trust that what we will receive is of greater value, and at the same time we acknowledge that the provision is still entirely from God. 

Surrendering something of one’s self is not purchasing; it’s making room.  The formula for a vow is not, Lord, I trade you this for that; nor worse, give me that and I will give you this.  The formula is, Lord, I create an emptiness. Fill it as You will.