Faith is a process of growth. It starts with our belief, and through trials and work it develops into a stronger and stronger faith, in what God can and will do. We see this development in many Bible Characters, but I want to concentrate on Samuel and David today.
Samuel was dedicated and given to God as a child by his mother Hannah. Hannah did this, because she was barren and God blessed her and her husband with Samuel. Hannah promised God, her child for God's service.
When the time came, Samuel was given to Eli, The High Priest, to raise as a Servant of God. One night, Samuel heard a voice calling him. Samuel ran to Eli, to see what the priest needed. Eli told Samuel, I didn't call go back to bed. This happened three times and on the third time Eli told Samuel to say, "Speak, Lord, for thy servant hears."
So Samuel said as he was told the next time the call came. Then the Lord spoke to Samuel about the impending doom that was to come to Eli's house, because of Eli's sons blaspheming God.
This was the first of many prophesies by Samuel, in the Bible. It established Samuel as God's Prophet and the Bible says none of Samuel's words fell to the ground. Meaning that every word out of Samuels mouth, came to pass.
God watched Samuel grow. God saw and appreciated how Samuel did his work in God's House. God started Samuel out with a small prophesy and eventually Samuel became The Prophet of Israel, anointing not only Saul, as king, but anointing David as King of Israel.
David grew up in the house of Jesse, with older brothers and sisters. David tended to the families sheep, and learned how to use a sling, a lyre, and write poetry and music, while tending his fathers sheep.
While David was tending His father's sheep, he chased off a bear and a lion, using his sling and stones. Later his mastery of these tools and instruments would help Him defeat Goliath, but also help him in service to God as the primary writer of Psalms.
God starts all of us out with belief. We can believe, just as Satan believes or we can start to test our belief, with actions and words.
Our faith in God grows with every trial we overcome. Our faith grows with every "valley of death" we traverse and come through safely. Our faith in God grows with every triumph over temptation that we endure. None of these victories are even possible without God in our lives.
God is our strength in times of trials. God carries us, as we traverse through the "valleys of death." God is our comfort and holds us as we go through life's temptations.