Ps. 51.15 (open lips, mouth of praise)

O Lord / open my lips
so that my mouth / can voice /your praise.

It seems clear that this verse should be read as a parrallel to the previous verse wherein David asked for deliverance from bloodguilt and said his tongue would then 'sing out your righteousness'. The reason this is important is because the opening lines of "opening my lips" is, in this context, to be understood as an aspect of God's deliverance and removal of David's bloodguilt/rebellion. David's inability to praise God has been gestured at throughout the second portion of the psalm: "cause me to hear joy and gladness, let the bones you have crushed rejoice" (vs. 8); "restore the joy of your salvation" (vs. 12). Furthermore, the mention of his "lips" and "mouth" should be understood in the context of the other bodily images of healing/recreation: "bones you have crushed rejoice"; "create for me a clean heart..and renew a steadfast spirit"; "tongue will sing out your righteousness".

These two observations solidify this verse's pointing to the previous verse and the deliverance imagery: David's sin/bloodguilt is similar to a sickness and something he needs to be delivered from. It is 'crushing his bones' and, perhaps most centrally, it has made his heart useless and not in need of healing but re-creation.  Here, it is seen as "shutting his mouth", sealing it to praise. David is, in other words, unable to praise God while his bloodguilt remains enemy(disease)-like implanted within him.

Lastly, there is another of our themes embodied in this verse: God opens the lips, and then David sings to God. What we see here is that David's bloodguilt is something that creates a situation wherein the only 'actor' can be God; only he can perform the necessary act of removal, cleansing and recreation. Here, only he can "open the lips". However, once that action is performed, the mutuality of covenant emerges. David is freed and empowered. And, in this freedom he turns to his God and "voices your praise". This freedom of David is seen in the "so that" and the "then" clauses: "then I will teach your ways to the rebellious..."; "then my tongue will sing out..."; "so that my mouth can voice...". The removal of rebellion and bloodguilt is to restore this freedom, this covenantal mutuality. It is here, in the re-empowered (and, indeed, re-created) David that we see the real effect of rebellion--the placing of the entire onus of the covenant onto God and his 'loving-kindness' and 'abudnant mercy' (vs. 1). It, in a sense, returns the covenant to its origin and destroys the inherent relationality that is sought by God in the covenant. The dialogue ceases and the only thing that can emerge is the monologue of God.