1 Sam. 18  After slaying Goliath, David was brought to Saul's house and made a leader in his army.  David prospered, but remained humble.  He even continued to play the harp for Saul when needed.
Saul's feelings towards David were spiraling downward:
V 9 - Saul was suspicious of David.
V10-11 Saul tried to intimidate David by throwing spears at him.
V 12  Saul was "afraid of David"
V15 Saul "dreaded" David
V 17 Saul wished David would be taken out by the Philistines
V21  Saul wanted David to marry his daughter, who would be a snare( a noose/ trap) to him.
V 25  Again Saul sent David out to the Philistines.. hoping he would die.
V29  Saul was even more afraid of David " Thus Saul was David's enemy continually"

Even under these circumstances, David remained loyal to Saul and faithful to God.  We are told that David prospered and that he behaved "more wisely than all the servants of Saul."  In spite of Saul's attitude towards David,  Jonathan and all of Judah loved David.  The Lord was with David.  Everyone knew it and that was what frightened Saul the most, and what made everyone else jubilant.

Chapters 19-20  tell the story of Saul's anger and hatred of David, contrasted with Jonathan's love and devotion to David.  As Saul seeks to kill David, Jonathan protects him.  David and Jonathan make a covenant between them and the Lord.  Their friendship was stronger than the father and son relationship between Saul and Jonathan.

Father in heaven, may Your Name be honored and Your will be done.  May Your Kingdom come.  Jehovah, the self-existant One Who reveals Yourself to us in Your holiness, it is to You we come, praising You and thanking You for the provisions that You have made for us.  As You prospered David through the troubles with Saul, will You enable us to stand firmly in Christ through the troubles of our society.  May we walk in wisdom and faith, by Your Spirit. May we serve You with peace in our hearts by the strength that You give us in Jesus Christ our Lord. Amen.