Leaving sins is, in and of itself, du’a.
(ie. just as sins come between a person and his du’a, likewise leaving sins makes the path of response easier)
—Sufyān al-Thawrī [161H/778CE]
Jami’ al-‘Ulum wal-Hikam, 1/276
(Read on pg 162, Yasir Qadhi, Du’a: The Weapon of the Believer. Al-Hidaayah Publishing & Distribution Ltd. Birmingham: 2003.)