Midrash su Salmi 71:11

"When he reached the cross-road (where there is a guide-post)," what does crossroad mean? Said R. Chisda: "This means when a scholar approaches his death." R. Nachman b. Isaac said: "This means a scholar who fears sin." Mar Zutra said: "This refers to a scholar who reaches such a stage as to report tradition in agreement with the prevailing law." In another way the above may be explained: A transgression destroyed a meritorious act, bat it cannot destroy the Torah. R. Joseph said that R. M'nachem b. R. Joseph interpreted the above passage just as if it were handed down from Mt. Sinai, and had Doeg and Achitoffel interpreted it in that sense they would have never decided to pursue after David. For it is written (Ps. 71, 11) Saying: 'God hath forsaken him; pursue and take him; for there is none to deliver.' What passage did they interpret to guide them in their theory [to pursue David?] The following passage (Duet. 23, 15) So that He sees no unseemly thing in thee, and turn away from thee. They did not know that although a transgression could nullify a commandment, nevertheless it could not destroy the Torah of [David]. "What is the meaning of the passage (Songs 8, 7) Man would utterly despise him? Said Ulla: "Neither like Simon the brother of Azariah, nor like R. Jochanan of the prince's family, but like Hillel and Shebna; for when R. Dimi came he said that Hillel and Shebna were brothers. Hillel devoted his time to the Torah, while Shebna devoted his time to business. At the end they said to each other: 'Come and let us be partners and share both worlds.' Whereupon a heavenly voice came forth saying (Ib., ib., ib.)If a man were to give all the wealth of his house for love, man would utterly despise him."