מה שאין כן אם לומד ומקיים המצוה באהבה לבדה כדי לדבקה בו על ידי תורתו ומצותיו, אינה נקראת בשם עבודת עבד

On the other hand, if one studies [Torah] and performs a commandment with love alone, in order to cleave to Him through [the study of] His Torah and [the performance of] His commandments, then this is not termed “service of a servant,”

והתורה אמרה: ועבדתם את ה׳ אלקיכם וגו׳ ואותו תעבודו וגו׳

whereas the Torah has declared:1 “You shall serve (vaavadetem) the L‑rd your G‑d....” This verb is cognate with the noun eved (servant or slave), and signifies service motivated by the fear and awe of G‑d; and it is likewise written:2 “Him shall you serve (taavodu)....”

וכמו שכתוב בזהר פרשת בהר : כהאי תורא דיהבין עליה עול בקדמיתא, בגין לאפקא מיניה טב לעלמא כו׳, הכי נמי איצטריך לבר נש לקבלה עליה עול מלכות שמים בקדמיתא כו׳, ואי האי לא אשתכח גביה לא שריא ביה קדושה כו׳

As explained in the Zohar (Parshat Behar): “Just like the ox on which one first places a yoke in order to make it useful to the world,...so too must a human being first of all submit to the yoke of the Kingdom of Heaven,... and only then engage in divine service; and if this [submission] is not found in him, holiness cannot rest within him....”

וברעיא מהימנא שם דף קי״א עמוד ב׳, שכל אדם צריך להיות בשתי בחינות ומדריגות

And (in Ra‘aya Mehemna, ibid., 111b) it is written that every man must in his divine service belong to two categories and levels,

והן בחינת עבד ובחינת בן

namely, the category of a servant, who serves his master out of fear, and the category of a son, who serves his father out of love.

ואף דיש בן שהוא גם כן עבד, הרי אי אפשר לבא למדריגה זו בלי קדימת היראה עילאה, כידוע ליודעים

And although one may find a son who is also a servant, it is impossible to attain to this degree without the prerequisite of the higher level of fear and awe known as yirah ila‘ah, as is known to the initiated.

It is clear from all the above that even if one loves G‑d, but lacks a fear of Him, his spiritual labors will not be of the kind that the Torah calls avodah, divine service. And should he fail in his attempts at awakening a fear of G‑d in his heart, he should at least arouse a feeling of fear and awe in his mind.