Even though the Jews diligently sought God in the pages of their Scriptures they failed to recognize Jesus for who He was. The Greek verb translated "search" could be an imperative (AV) or an indicative (NASB, NIV). The context favors the indicative mood. The Jewish leaders of Jesus" day were serious students of the Old Testament, but they studied it for the wrong reason, namely, to earn eternal life through their effort (cf. Romans 7:10; Galatians 3:21). [source][source][source]
"After the destruction of the temple of Solomon in586 B.C, the Jewish scholars of the Exile substituted the study of the Law for the observance of the temple ritual and sacrifices. They pored over the OT, endeavoring to extract the fullest possible meaning from its words, because they believed that the very study itself would bring them life." [1][source]
The study of Scripture had become an end in itself rather than a way of getting to know God better. Their failure to recognize Jesus as the Messiah testified to their lack of perceiving the true message of Scripture (cf. John 1:45; John 2:22; John 3:10; John 5:45-46; John 20:9; 2 Corinthians 3:15). Life comes through Jesus, not through Bible study ( John 5:21; John 5:26; cf. John 1:4; Romans 10:4), even though it is through Bible study that one comes to know Jesus. As John the Baptist, the Old Testament pointed away from itself to Jesus. [source][source][source]