"God willing" (Im yirtzeh HaShem).

With every action that you do, say "God Willing." (Derech Hayim, 7-24)

This expression is used to separate us from the false belief that our will is enough to bring something into the world, and to remind us that everything that happens happens only when it is God's will. For example, when making an appointment: "I will meet you at six P.M. on Wednesday, God willing." Whether or not the appointment can be kept depends not only on us but also and primarily on God's will.

Yitzhak Buxbaum in Jewish Spiritual Practices