Dhammapada (verses 121-122):
"Do not think lightly of evil, saying, 'It will not come to me.'
Drop by drop is the water pot filled.
Likewise, the fool, gathering it little by little, fills himself with evil."
"Do not think lightly of good, saying, 'It will not come to me.'
Drop by drop is the water pot filled.
Likewise, the wise one, gathering it little by little, fills himself with good."
It is true of all things that one need ponder the consequences of their actions before performing them. This is a primary principle. Do not prepare a resting place that you refuse to lie in. The problem here is that not all actions carry consequences in the present. Some are edged out, even to the last of your days. These are the consequences we cannot see. What we cannot see, we are unlikely to prepare for.
This is a grievous thing. Whosoever acts on consequences rather than their principles will commit acts of evil when no judgement is near, and shy from the face of good if it lacks reward.
For these people evil will return to their household in the night. It will strike them with no warning, and they will say, "What have I done to deserve this?" For they have forgot their acts of evil, but the bond of wickedness will always, in its time, reach maturity, and a hidden cost is always greater than a seen one.
So I beg of you, be good for good's sake. It was said by Emerson that "the reward of a thing well done is having done it." So do good, for the cost is plain, and laid out before you, and the reward, although hidden, is sweet, and will overtake you in your time of need. You will say, "What have I done to deserve this?" For you have forgot your acts of good, but the bond of righteousness will always, in its time, reach maturity, and the reward of the pleasant should be preferred to the castigation of the wicked.