From Mu'az bin Jabal radiyallahu 'anhu he said, Rasulullah sallallaahu' alaihi wasallam said, "Who is the end of speech Laa ilaaha illallah, he will enter Paradise." (Ahmad, Abu Daud and Hakim, hadith hasan).
Therefore if any man will die (the spirit is almost out), let him ditalqinkan (guided) with the sentence tauhid, to remind him with the sentence and in order to utter it at the end of his life. From Abi Sa'id al-Khudri aradiyallahu 'anhu he said, Rasulullah shallallahu' alaihi wasallam said, "Talqinkanlah people who almost died among you 'laa ilaha illallah" (Muslim)
Should the sentence be spoken slowly in the sense not too fast to be imitated easily. When he has said, then talqinnya do not have to be repeated again, unless he said the other words then the talqin was repeated again. This is the preferred talqin. As for after the exit of the spirit, then the talqin is not disyari'atkan anymore. Due to the absence of a shahih sunnah from the prophet about it.