isaiah 38:3 And said, Remember now, O LORD, I beseech thee, how I have walked before thee in truth and with a perfect heart, and have done that which is good in thy sight. And Hezekiah wept sore. - Free Bible Online

      3. He mentions his past religious consistency, not as a boast or a ground for justification; but according to the Old Testament dispensation, wherein temporal rewards (as long life, &c., Ex 20:12) followed legal obedience, he makes his religious conduct a plea for asking the prolongation of his life.
      walked--Life is a journey; the pious "walk with God" (Ge 5:24; 1Ki 9:4).
      perfect--sincere; not absolutely perfect, but aiming towards it (Mt 5:45); single-minded in walking as in the presence of God (Ge 17:1). The letter of the Old Testament legal righteousness was, however, a standard very much below the spirit of the law as unfolded by Christ (Mt 5:20-48; 2Co 3:6, 14, 17).
      wept sore--JOSEPHUS says, the reason why he wept so sorely was that being childless, he was leaving the kingdom without a successor. How often our wishes, when gratified, prove curses! Hezekiah lived to have a son; that son was the idolater Manasseh, the chief cause of God's wrath against Judah, and of the overthrow of the kingdom (2Ki 23:26, 27).

JFB.