1Then Samuel took a flask of oil and poured it on his head and kissed him and said, “Has not the LORD anointed you to be prince over his people Israel? And you shall reign over the people of the LORD and you will save them from the hand of their surrounding enemies. And this shall be the sign to you that the LORD has anointed you to be prince over his heritage.
Kissing Saul was an act of respect and a recognition (by Samuel) of Saul’s new role as ruler of Israel.1
1 Then Samuel took a flask of oil and poured it on his head and kissed him and said, “Has not the LORD anointed you to be prince over his people Israel? And you shall reign over the people of the LORD and you will save them from the hand of their surrounding enemies. And this shall be the sign to you that the LORD has anointed you to be prince over his heritage.