If you ask me, it is nothing but an honor and a blessing to be guided by Allah to Work for Him.
True, if Allah did not call you, and guide you, you will not be Working for Him. You will be doing a million other things. God only knows what.
As people get older and less able, they still have to continue doing what they can, while they can, in trying to take Islam to as many people as possible.
That is what we mean when we say: Taking the Qur'an to Every Home and Heart that Needs It -- and Which One Does Not.
Everything else in creation works for Allah. 24-7. So why shouldn't we fall in line?
The Messengers of Allah, Alaihimus Salam, faced many tests in the course of doing their job of inviting people to Allah. Why do we feel that we would not be tested, although our tests will only be very small in comparison?
As for the people you try to invite to Allah, they are always going to react in all kinds of different ways to your call. But that is the nature of this work.
Our job then is only to convey the message and Allah determines the results.
Even though, to tell you the truth, he determines the means and the methods too.
Wa Maa Alaika Illal Balaagh, says Allah in the Qur'an.
What choice do we have after we have been guided by Allah other than to serve him?
And Work for Him?
May Allah keep all of us on course, Working for him, for as long as we live!