Psalms 19:14

‘Let the words of my mouth and the meditation of my heart,

Be acceptable in your sight,

O YHWH, my rock, and my redeemer.

So does he want to be right in mouth and heart so as to behave in a way that is totally acceptable to God. And he finishes with the heartfelt prayer that in both the words of his mouth and the thoughts of his heart he might be acceptable in God's sight. He recognises that it is what is in the heart that defiles a man (Mark 7:20). As a man thinks in his heart, so is he (Proverbs 23:7). And that from the abundance of the heart the mouth speaks (Matthew 12:34), so that by our words we will be accounted righteous or condemned (Matthew 12:37).

‘Be acceptable.' The word connects with acceptability with God achieved through sacrifice (Leviticus 1:3). He desires that his words and thoughts be acceptable offerings to God, free from all taint and blemish.

For YHWH is his rock and his redeemer, and his desire is to please Him. The idea of the rock is of a solid and sure foundation (Psalms 18:1; Isaiah 26:4 in context), and includes the idea of protection (Isaiah 32:2). The idea of a ‘redeemer' is of one who acts on another's behalf, delivering from bondage and from sin, and ensuring his reinstatement in blessing and favour, by the expenditure of saving effort and/or by the payment of a price.