The P in Tulip

Some say the P in tulip stands for perseverance of the saints
others the preservation of the saints.

I will sing of your steadfast love, O Lord, forever; with my mouth I will proclaim your faithfulness to all generations.
I declare that your steadfast love is established forever; your faithfulness is as firm as the heavens.
You said, “I have made a covenant with my chosen one, I have sworn to my servant David:
‘I will establish your descendants forever, and build your throne for all generations.’”
Ps 89:1-4 

Sometimes I despair. I am a sinner. I cannot not commit wrongdoing. Even when I do the right thing, it is for selfish reasons. And so I come to be convinced that I am bound to fall away; God's grace isn't sufficient for someone like me.

But this falling away "cannot possibly happen. God’s plan cannot be changed; God’s promise cannot fail; the calling according to God’s purpose cannot be revoked; the merit of Christ as well as his interceding and preserving cannot be nullified; and the sealing of the Holy Spirit can neither be invalidated nor wiped out."
Canons of Dort 5.8 

I thank you, my Creator, for the obedience of Christ and the intercession of your Spirit. Help me never to despair, but to believe your promises, sealed with the blood of your Son, in whose Name I pray as he taught me: Our Father...