This is a great secret from the secrets of Tawhid. The heart cannot become firm, it cannot find satisfaction and it cannot find tranquillity except by reaching out to Him. Everything that is loved and desired besides Him, it must be desired for other than His sake. The One who is desired, the One who is beloved in and of Himself and with whom all matters find their final goal is only one. It is impossible that the final goal be to two destinations just as it is impossible that the beginning of the creation be from two sources.
The person whose love, desire, will and obedience ends at other than Him will find it rendered null and void; it will disappear and leave him no matter how great his need be of it. However, the person whose love, desire, will, obedience, awe and reverential fear ends at Him, far removed is He from imperfection, he will find himself winning His favours, bliss and rapture, magnificence and splendour, and eternal felicity.
The servant continuously finds himself altering between the laws of commandments and the laws of decree. Therefore, he is always in need of help in fulfilling the commandments, grace and leniency at the onset of the calamity. It is the extent to which he establishes the obligations that determine how much grace the servant will receive at the onset of the calamity. If he completes his obligations both inwardly and outwardly, he will receive grace and leniency, both inwardly and outwardly. If, however, he merely establishes the outward form [of what is prescribed] without establishing their [inward] reality, he will receive an outward grace but his inner lot will diminish.
If it is asked, ‘Just what is this inner grace?’
[I say in reply:] It is that tranquillity and satisfaction that the heart attains at the onset of the calamity coupled with the removal of unrest, confusion and despair. The servant surrenders and submits himself before his Lord and Master and emerges in a state of quietude and peace, looking on at Him with his heart; his soul at rest. His witnessing Allah’s grace has distracted him from the severity of the circumstance. He knows that Allah’s choice and decision is for the best and this diverts him from feeling the calamity. He knows that he is nothing but a mere servant upon whom the decrees of his Master take effect, and he can either be pleased with them or angry with them. If he is pleased, he will attain divine pleasure and if he is displeased, his lot will be divine displeasure. Therefore, this inward grace is the fruit of his inward act [of being pleased with Allah]. It increases as it increases and decreases as it decreases.
Ibn al-Qayyim, al-Fawa’id. Translated by Abu Rumaysah