Samuel Develops As A Prophet (1 Samuel 3:19-20)
The phrase ‘YHWH was with him' regularly indicates His acting through the one in mind. Note its use of Abraham (Genesis 21:22; Jacob (Genesis 28:15; Joseph (Genesis 29:2; Moses (Exodus 3:12); Joshua (Joshua 1:5); Gideon (Judges 6:16); David (1 Samuel 16:18; 1 Samuel 18:14). Samuel was following in a line of powerful men of God.
‘ And Samuel grew, and YHWH was with him, and let none of his words fall to the ground.'
As Samuel grew up YHWH was with Him. (See above). He now ‘knew YHWH' and received His word (compare 1 Samuel 3:7). And as he passed them on to the people YHWH let none of his words be wasted, and fulfilled all that was promised. Everything that he spoke came about (compare 1 Samuel 9:6), and came to the people as the oracle of YHWH. His words were certainly going to be needed. They were entering one of the darker periods of Israel's history in the face of continued Philistine oppression which threatened to engulf them.
This description takes us beyond 4:1b-7:2, which was happening while Samuel was ‘growing'. It is a ‘flash forward'. There is no reason to think that Samuel was involved in the disastrous (though understandable) decision to take the Ark into battle. That was the decision of the priests.
‘ And all Israel from Dan even to Beer-sheba knew that Samuel was established to be a prophet of YHWH.'
And the result was that all Israel ‘from Dan to Beersheba' knew that Samuel was established to be a prophet of YHWH. The news spread everywhere among the tribes. At last YHWH was speaking again. He had raised up a prophet like to Moses (Deuteronomy 18:15).
The description ‘from Dan to Beersheba' was a standard expression encompassing all the tribes of Israel, Dan being the northernmost point and Beersheba the southernmost. Compare Judges 20:1; 2Sa 3:10; 2 Samuel 17:11; 2 Samuel 24:2; 2Sa 24:15; 1 Kings 4:25, and regularly in the book of Samuel. This did not refer to the area of Samuel's judgeship. It referred to his status as a prophet.
“Was established.” That is, all recognised that his position was ‘made sure' by YHWH. Happy the man on whom God sets His seal (which He does in a more general way on all who are His - Ephesians 1:13; Ephesians 4:30; but in a special way on those whom He chooses).