Typically we relate large muscles to strength, and generally this isn't to far off from the truth. But, do bigger muscles mean greater strength?
First lets breakdown where strength comes from. Strength inherently comes from the Central Nervous System's ability to engage the muscles. This happens in 2 ways; First the Number of Muscle Fibers the CNS can recruit at once is referred to as Motor unit Recruitment. Second the speed at which those fibers can activate is called Rate Coding.
We can break down each of these terms, but for now let's continue with what we're here for. Based on this it would seem sensible that larger muscles give the CNS more muscle fibers to recruit from, which is correct. However, that's only half the battle and doesn't take into account the efficiency of the CNS.
Next the importance of Rate Coding. The CNS cannot send weaker or stronger signals to engage more muscle activation, instead Rate Coding comes the the CNS' ability to increase the frequency at which the signal is sent.
The next point here is that strength in certain movements ie; the bench/squat/deadlift is a specialized motor pattern. That means for a large part of strength in these movements it is a learned motor pattern of the CNS. Years of repetitions have trained the CNS how to get better at this specific motor pattern.
Putting it all together. Muscle size certainly plays a role in strength via it's ability to offer the CNS more muscle fibers to recruit from. The CNS can be trained to be more efficient with less muscle fibers based on Motor Unit Recruitment.
Next, the CNS can also be trained to increase the frequency in which it sends signals known as Rate Coding allowing the muscles to activate faster achieving a higher level of strength.
Lastly, learning a set movement pattern, and then spending thousands of reps specializing your body to this movement pattern can grant you a great deal of strength.
In closing, building bigger muscles will inevitably help most people become stronger. Strength ultimately comes from the CNS, and it's ability to recruit muscle fibers and activate them at maximum frequency for explosive strength.