There are no contradictions with God being omniscient and omnibenevolent and we still needing to do our bit of effort to attract his grace.
Lord Shiva, in the two verses given below, has nicely explained, why our efforts will be needed.
GavAm sarpih sharirastham na karotyanga poshanam |
rachitam dattam punastAmeva poshayet || (78)
sharirasthA sarpivat parameswari |
VinA chopAsanAm devi na dadAti
phalam nrinAm (79)
Cream (sarpi), as long as it lies in the body of the cow, does not
nourish anyone. But when [with effort] it is collected, treated and used, it does
promote nourishment. (78) The Divine (Parameswari) is likewise there
spread in each body; but without proper adoration and evocation,
upasana, it (she) does not yield fruit to man.
KulArnava Tantram Chapter 6, Verses 78, 79.
So, efforts from our side is very much needed. In case of the verses the effort is that of collecting the cream from the cow to extract and utilize the cream's nourishing power.
The purport of these verses is that just like the utility of Cow's cream (its nourishing power) is ever existing in its body but without our efforts to extract it and make it usable for practical purposes, its as good as simply non-existent, similarly God's grace, which is always existing everywhere, is unachievable without the devotee's sincere efforts.
IMO, to expect things to happen automatically by God's will or grace is against the natural order of things.
We need to do either Sacrifice (loosely translated as Yajna) or perform austerity (Tapas).
Even the Purusha (of the Purusha Suktam) offered himself as the offering to ensue creation at the onset. So, creation did not happen automatically. It needed something and sacrifice was that thing in that case.
Yat purushena havishA (1)
devA yajnam atanvata (2)
asyasid Ajyam (3)
grishma idhmah sharad havihi (4) ||
With Purusha as offering (1) the devAs performed a sacrifice: (2) the spring was the Ajya, (3) summer the fuel (samit), and autumn (sharat)
the offering (4).
Rig Veda 10.90.6
Similarly, if we study the "manifestation of Goddess LalitA" episode of the Brahmanda PurAna, we will find that, in spite of finding the Gods and creation itself in deep trouble, Goddess did not automatically emerged and been the savior. It needed then too, a huge sacrifice where all Devas and the whole creation was offered as the Havi (oblation). And it is only then LalitA Paramesswari manifested out of the Homa-Kunda.
Maha Shambhu explained:
A. This is called as Maha Yaga. (great fire sacrifice)
B. I am (assuming the form of Vayu) the Hota (the priest who makes the
offerings in a Homa) in this Yaga (fire sacrifice).
C. My Chidagni itself is the fire in this Yaga.
D. The last of the seven seas, i.e., Jala Samudra (Water Sea) has now
dried up. The huge pit so formed itself is the Homa Kunda (fire pit
where Homa is performed)
E. The remaining six great oceans constitute the six drops of ghee
which is used as offering.
F. Srishti (creation) is of five types (i) Manasa Srishti (ii)
Jarayavee Srishti (creation-taking place through the womb.
G. Human beings), (iii) Anda Srishti (creation taking place through
eggs) (iv) Swedaja Srishti (creation taking place through sweat) and
(v) Udbhijja Srishti (creation taking place by sprouting). These five
Srishtis (creations) are the sacrifice animals in this Maya Yaga.G.
Bhoomi (land), Parvata (mountains), Jala (water), Vayu (air) and
Akasha (space) these five are the substances used in this fire
sacrifice. Agni element (one of the five elements) being a part of my
Chidagni can not be a substance to be offered.
H. At the end of this great fire sacrifice, all of you (the performers
of the Yaga) should jump in to the Homa Kunda (fire pit). While doing
so, you must possess absolute devotion.
I. Then, Lalita Parameshwari will manifest.
Apart from sacrifice, Tapas or austerity also works and is needed to achieve anything whether it's something small or big.
11.234. All the bliss of gods and men is declared by the sages to whom the Veda was revealed, to have austerity for its root,
austerity for its middle, and austerity for its end.
11.237. Medicines, good health, learning, and the various divine stations are attained by austerities alone; for austerity is the
means of gaining them.
11.243. The lord, Pragapati, created these Institutes (of the sacred law) by his austerities alone; the sages likewise obtained (the
revelation of) the Vedas through their austerities.
Verses from Manu Smriti
So, even Gods can't expect things to happen on their own, they have to do their bit of UpAsana, whether in the form of Sacrifice or Austerity.
Even the Lord of creation can not create without Tapas.
With such being the Divine Law, i think its extremely unreasonable to expect God showering his grace on us without we doing anything to earn that grace.
That's why its being said:
VinA ChopAsanAm Devi na dadAti phalam nrinAm .... DhyAtah smritah
pujito vA stuto vA namitohapi vA..
Without worship, Devi does not give sAdhaka the fruits. One has to
meditate upon her, remember her, worship her or please her (by recting
stotrams) or offer prostrations to her..