1 Chronicles 23:1

So when David was old and full of days
Perhaps was now in the last year of his age, about seventy years old, though before he was bedridden; see ( 1 Chronicles 28:2 ) ,

he made Solomon his son king over Israel;
declared him to be his successor; this was before the affair of Adonijah, for then he ordered him to be anointed king, and placed on the throne; and this aggravated the rebellion of Adonijah, that it was against the declared and known will of his father.