Anfangen ist leicht
Anfangen ist leicht, beharren eine Kunst. Sustainability of any project is key to its success and not the commencement of the project.
Alte Füchse
Alte Füchse gehen schwer in die Falle. (An old fox understands a trap). Emmanuel Strauss
Alles zu seiner Zeit
Alles zu seiner Zeit. (“all in good time”), or idiomatically (“patience is a virtue”). If you are desiring to have something and it is taking forever to materialize, this is the time to be patient and keep working at it.