עשה מאהבה ועשה מיראה. עשה מאהבה שאם באת לשנוא דע כי אתה אוהב ואין אוהב שונא. עשה מיראה שאם באת לבעוט דע שאתה ירא ואין ירא בועט. (ברכות פרק ט: ה, סז,א)
The Talmud Yerushalmi gives us advise on how to worship God and perform His commandments. ‘Hating’ is the opposite of ‘loving’ which connotes “accepting God”, while “rebelling” refers to disobeying Him.
On the one hand one should strive towards worshipping God out of Love, i.e. because one accepts God as the Sovereign. On the other hand one should always worship God with some measure of fear. One may reject a government but may still abide by its laws in fear of the consequences!
The reasoning for this imperative is practical and pragmatic. The Talmud Yerushalmi explains that if you lapse in your Love for God, you will still observe His commandments because you fear Him. If you lapse in fear of God you will still follow his commandments because you love him and have come to accept Him. Only a combination of Love and Fear can make up the formula that ensures unfailing observance!
A person can not be assumed to be completely in touch with his inner-self and can never be absolutely sure of his true disposition at a given moment