It means that we love God so much that we hand ownership of ourselves over to him, as when an Israelite in Bible times loved his master so much that he obligated himself to him permanently as a slave.
وهذا يعني ان نحب الله كثيرا الى حد ان نسلِّم انفسنا له ،‏ مثلما كان العبد الاسرائيلي في ازمنة الكتاب المقدس يحب سيده الى حد الالتزام بالبقاء عبدا له .‏