First, you must have Right View (samma ditthi), so that when you have the effort, it will be the Right Effort and when you have the resolve, it will be the Right Resolve. Without Right View, you will be running for miles in the wrong direction.
This is why Right View is the forerunner of the path.
"Of those, right view is the forerunner. And how is right view the
forerunner? One discerns wrong view as wrong view, and right view as
right view. This is one's right view. .....
"And what is the right view that is noble, without effluents,
transcendent, a factor of the path? The discernment, the faculty of
discernment, the strength of discernment, analysis of qualities as a
factor for awakening, the path factor of right view in one developing
the noble path whose mind is noble, whose mind is without effluents,
who is fully possessed of the noble path. This is the right view that
is noble, without effluents, transcendent, a factor of the path.
MN 117
The Buddha taught to strive with heedfulness (appamādena sampādethā”ti), as the pursuit of liberation is an urgent task. The famous last words of the Buddha, before his passing away, were "vayadhammā saṅkhārā appamādena sampādethā”ti".
Then the Gracious One addressed the monks, saying: “Come now, monks,
for I tell you all conditioned things are subject to decay, strive on
with heedfulness!” These were the last words of the Realised One.
DN 16
There's Right Effort (samma vayamo):
"And what, monks, is right effort? (i) There is the case where a monk
generates desire, endeavors, activates persistence, upholds & exerts
his intent for the sake of the non-arising of evil, unskillful
qualities that have not yet arisen. (ii) He generates desire,
endeavors, activates persistence, upholds & exerts his intent for the
sake of the abandonment of evil, unskillful qualities that have
arisen. (iii) He generates desire, endeavors, activates persistence,
upholds & exerts his intent for the sake of the arising of skillful
qualities that have not yet arisen. (iv) He generates desire,
endeavors, activates persistence, upholds & exerts his intent for the
maintenance, non-confusion, increase, plenitude, development, &
culmination of skillful qualities that have arisen: This, monks, is
called right effort.
SN 45.8
There's also the part about the right balance between energy (vīriya) and serenity (samatha). Not too much energy in one's effort, otherwise it makes one restless. And also not too little energy in one's effort, otherwise one becomes lazy.
The Buddha said to him, “Soṇa, ... didn’t
this thought come to your mind: ‘I am one of the Buddha’s most
energetic disciples. Yet my mind is not freed from defilements by not
grasping. ...
“Yes, sir.”
“What do you think, Soṇa? When you were still a layman, weren’t you a
good player of the arched harp?”
“Yes, sir.”
“When your harp’s strings were tuned too tight, was it resonant and
playable?”
“No, sir.”
“When your harp’s strings were tuned too slack, was it resonant and
playable?”
“No, sir.”
“But when your harp’s strings were tuned neither too tight nor too
slack, but fixed at an even tension, was it resonant and playable?”
“Yes, sir.”
“In the same way, Soṇa, when energy is too forceful it leads to
restlessness. When energy is too slack it leads to laziness. So, Soṇa,
you should apply yourself to energy and serenity, find a balance of
the faculties, and learn the pattern of this situation.”
“Yes, sir,” Soṇa replied. ...
After some time Soṇa applied himself to energy and serenity, found a
balance of the faculties, and learned the pattern of this situation.
Then Soṇa, living alone, withdrawn, diligent, keen, and resolute, soon
realized the supreme culmination of the spiritual path in this very
life.
AN 6.55
It's perhaps in this last sutta quote, plus Right View, that you find the balance of your two quotes.
