Musar zu Ejchah 2:8

I have stipulated the principle that G–d-Torah-lsrael are linked together, the Torah being G–d's imprint, whereas Israel is the Torah's imprint. By keeping this point in mind the statements of our sages about the commandment to procreate can be understood (as I explained in my introduction to chapter six of tractate יבמות). Every "wall" is actually composed of a double wall, as רשי has explained on Lamentations 2,8, on the words ויאבל חיל וחומה, "He made both wall and rampart wail." Similarly all the four walls are to be viewed as double walls. Repentance can be expressed visibly by fasting, donning of sackcloth and public prayer, or it can be expressed invisibly by a heart full of remorse, good resolutions, etc. It can be motivated by fear of retribution, or it can be due to a feeling of love for G–d. The invisible repentance is the real repentance. This is why it is called אמת, "truth". It is an offshoot of the attribute אמת.