Tehillim
בראשית מז,כט: וַיִּקְרְ בוּ יְמֵי־יִּשְ רָאֵל לָמוּת
The Baal HaTurim writes that the phrase ויקרבו ימי also occurs by the death of Dovid haMelech. The Medrash states that HaShem told Dovid to compose 147 kepital corresponding to the years of the life of Yaacov. You should also merit that your son also reign during your lifetime.
Yaacov is connected to Tehillim that during the years that he worked by Lavan he would not lie down at night (since he was hired to watch the flocks). Therefore, he stays awake and recited the entire Tehillim.
Although the chapters divisions of the other books of Tanach are not of a Jewish origin, the common division of Sefer Tehillim is ancient. The usual count is 150, but some sources have a few chapters joined as one, which result in the total of 147.
תהלים
קאפיטעל (פרק)Standardירושלמימס' סופריםמדרש תהלים#1, #2Counted as twoCounted as oneכלו תפלות דוד 72nd 71st (70 years of King Dovid)#114, #115Counted as twoCounted as one#116, #117Counted as twoCounted as oneReasonWhen not fully doing the Will of G-dWhen doing the Will of G-dTime of King Dovid and of MoshiachTotal150147