Genesis 37:34

And Jacob rent his clothes
As expressive of his grief and mourning for the death of his son, as he supposed: and put sackcloth upon his loins;
put off his usual apparel, and put on a coarse garment on his loins next to his flesh, as another token of his great trouble and affliction for the loss of his son; which though afterwards was frequently done in times of public or private mourning, yet this is the first time we read of it; whether Jacob was the first that used it, whom his posterity and others imitated, is not certain; however it appears that this usage, as well as that of rending clothes on sorrowful occasions, were very ancient: and mourned for his son many days:
or years, as days sometimes signify; twenty two years, according to Jarchi, even until the time he went down to Egypt and saw him alive.