1 Samuel 16:2
And Samuel said, How can I go? if Saul hear it, he will kill me. And the LORD said, Take an heifer with thee, and say, I am come to sacrifice to the LORD. And Samuel said, How can I go? if Saul hear it, he will kill me. And the LORD said, Take an heifer with thee, and say, I am come to sacrifice to the LORD.
God sent Samuel to Jesse the Bethlehemite because He had provided Himself a king among Jesse's sons, to anoint David the son of Jesse as king of Israel and successor to the kingdom over which Saul had reigned. At that time David was the youngest son, living in retirement as a humble shepherd boy keeping his flocks on the hills around Bethlehem. Samuel feared that if Saul heard of the mission Saul would kill him, yet he did what the Lord spoke and obeyed God's direction to go.
God told him to fill his horn with oil and go, to take a heifer with him and say he had come to sacrifice to the Lord, to call Jesse to the sacrifice, with the promise that God would show him what to do and that he should anoint for God the one God named to him. He came to Bethlehem, where the elders of the town trembled at his coming and asked whether he came peaceably, and he answered peaceably. The elders accepted the invitation to the sacrifice and he also called Jesse and his sons, and the altar was built and the sacrifice made ready before the offering feast.
God chose David over a son who looked more impressive, because the choice rested on the heart and character rather than outward appearance, and David's faithfulness and courage as a shepherd had prepared him to lead God's people, and God gave him a prudent and understanding heart. Abner knew the Lord had appointed David to the throne, yet after long hunting and pursuing David he was unwilling for David to succeed Saul. The account sets David, to whom God gave the promise of the throne while still a shepherd boy and lad, against Saul the established king and monarch who was determined to keep his power and bent on holding it fast. Though utterly helpless in himself, David trusted the word and promise of God against human power, and thus withstood the power of the whole world, making him an example of trusting God's Word while opposed. His stand shows that saving faith is confiding trust by which, through the grace of Christ, the soul becomes a conquering power able to withstand the power of the whole world.