Kept to flourish like a green olive tree

 

But I am like a green olive tree in the house of God;

I trust in the mercy of God forever and ever.

I will praise You forever,

Because You have done it;

And in the presence of Your saints

I will wait on Your name, for it is good. (Psa 52)

This verse tells us how trust in the mercy of the Lord creates an atmosphere of growth, protection from evil and fruitfulness. In this Psalm, David had almost lost his life because Doeg had told Saul where he was hiding.
God gave him food (the shew bread in the temple), a weapon - Goliath's sword which was a the temple and also protection when he was at Acish's palace - the philistine King.

The Mercy of the Lord kept David and sustained him just like a healthy Olive tree in a secure place.
Trust in the Mercy of the Lord forever and ever.