Z ‘This poor man cried, and YHWH heard him,
And saved him out of all his troubles.
CH The angel of YHWH encamps round about those who fear him,
And delivers them.'
David was duly humbled by his experiences, which, although he may not have realised it, were preparing him for greater things. And when he thought back on how he had escaped from Saul, and now from Achish, he recognised his own weakness and helplessness in both situation, calling himself a ‘poor man', lowly in the sight of God and of men. He recognised himself for what he was. There was no pretence or arrogance with David. He openly acknowledged his own undeserving, and that he stood with the meek of Psalms 34:2. But he also recognised the goodness of YHWH towards him, and was full of gratitude. Isaiah tells us in a similar vein that ‘God dwells in the high and holy place -- with him who is of a contrite and humble spirit, to revive the spirit of the humble, and to revive the heart of the contrite one' (Isaiah 57:15).
His experience had brought him out into a large place, for it had made him realise that while Achish had been surrounded by his fierce warriors, he himself had had even mightier protection. He had been under the protection of the Angel of YHWH, Who had delivered him from all his troubles, in spite of their magnitude. It had brought home to him that all who feared YHWH were ‘surrounded' by the Angel of YHWH, the very active presence of YHWH, and could therefore be sure of deliverance. Compare how Paul also tells us that ‘your lives are hid with Christ in God' (Colossians 3:3). We too are ‘surrounded' by the Angel of YHWH. We are reminded here of the three men thrown into the fire because they stood firm for God, only to find themselves accompanied there by one who was like the Son of God Who kept them safe from harm (Daniel 3:25).
The Angel of YHWH is mentioned a number of times in the Old Testament. He can speak of himself as YHWH, and yet is in some ways differentiated from YHWH (see Genesis 16:10; Genesis 16:13 in context; Genesis 21:17-18; Genesis 22:11; Exodus 23:20; Judges 13:16-18; Zechariah 1:12-16; Zechariah 3:1-2). He is called ‘the Angel of His presence' (Isaiah 63:9). And there is inter-personal communication between the Angel and YHWH (Zechariah 1:12). In this figure we have revealed to us, along with the mention of ‘the Spirit of YHWH', a first indication of the triunity of God.