That was so with Jonathan. He was the son of Saul and thus in line to be king over all Israel.
فَقَدْ كَانَ عَرْشُ إِسْرَائِيلَ مِنْ حَقِّهِ ،‏ إِلَّا أَنَّ ٱللهَ ٱخْتَارَ دَاوُدَ ،‏ شَابًّا أَصْغَرَ مِنْهُ بِكَثِيرٍ ،‏ لِيَكُونَ ٱلْمَلِكَ .‏