17:3 And the LORD was with Jehoshaphat, because he walked in the first ways of his father David, and sought not unto Baalim;
17:4 But sought to the LORD God of his father, and walked in his commandments, and not after the doings of Israel.
After the Jewish custom of calling a family, or tribal head, father; e.g. John 8:53 .
17:6 And his heart was lifted up in the ways of the LORD: moreover he took away the high places and groves out of Judah.
i.e. the ten-tribe kingdom.
17:14 And these are the numbers of them according to the house of their fathers: Of Judah, the captains of thousands; Adnah the chief, and with him mighty men of valour three hundred thousand.
high places (See Scofield "1 Kings 3:2") .
three hundred thousand
(See Scofield "1 Corinthians 10:8") .