Shaykh Ahmad Ali Lahori (Allah have mercy on him) said,

‘The spiritual effulgent blessings (faiz) that a disciple attains by being in the company of a perfect Shaykh can also be effectively accquired from the letter of the Shaykh. This is because when the seeker shakes hand with the Shaykh he derives blessings (tawajjuhat) through touch, when Shaykh observes him he derives benefit from the sight. And when the Shaykh responds to the disciple’s letter, the blessings from his hand, sight and mind all are concentrated in that writing.

Therefore, it is essential that the murid not only reads the letter with full concentration but he should show perfect reverence and full devotion to it in order to benefit from the three fold spiritual blessings.’

Shaykh al-Tafsir kay hairet angez waqeyat, page 277