Jannah is an abode for the people who will reach there after achieving Tazkiya of body and soul. This means that the same person knows the value of Tawheed and value of Tazkiya. How can then he/she, who proved himself/herself to be a pure soul and passed the test, can ever feel any impure feelings/thoughts, especially after seeing God with His/Her own eyes and after witnessing Jannah with His/Her own eyes. In Jannah, that level of purity would reach its apex w.r.t every emotion and every thought. Same is the case with the Mother whose son will be sent to Hell, for her, the importance of these factors will overweigh the fact that her son has been sent to hell beacuse to her, the achievement of Tazkiya and the approval of her Lord would matter more. This is where her peace would lie.

An example of this can be seen in this world, when first Caliph’s Abu Bakar’s (rta) son told him after he reverted to Islam that during battle of Badr, his father Abu Bakar (rta) came under the shadow of his sword many times but he let him go, and in return, Abu Bakar (rta) replied that had he come under the shadow of his sword instead, he wouldn’t have let him go.