וַיָּבֹ֤א דָוִד֙ אֶל־שָׁא֔וּל וַֽיַּעֲמֹ֖ד לְפָנָ֑יו וַיֶּאֱהָבֵ֣הֽוּ מְאֹ֔ד וַֽיְהִי־ל֖וֹ נֹשֵׂ֥א כֵלִֽים׃
And David came to Saul, and stood before him; and he loved him greatly; and he became his armour-bearer.
Read kabbalistic (mystical) interpretation of I Samuel 16:21: and classical mystical sources.